The primary purpose of the Batcave in every single incarnation of the character is that it's the command center for Bruce's crime fighting operation. There are many monitors and computers and scanners and communications equipment, and behind each you have servers and routers and high-speed internet connections. According to the character's mythology, the Batcomputer is on par with the FBI computers. And, it'd have to be -- he's doing the same job. He needs access to the same criminal record databases, etc.
The difference is the FBI has entire rooms full of people who do nothing but maintain their systems. Somebody who knows where each network cable goes.
So who's going to handle Wayne's Internet security, and program all of his proprietary software? He doesn't just have Windows 7 Professional on his Batcomputer. Otherwise, what use is it?
"Ok, Mr. Wayne, so you need our best system, only with bat logos everywhere. And we can't tell anyone what we are working on. No problem!"
And this equipment will break. Even if Wayne wasn't the target of every criminal hacker in the world, the Batcave itself will do the damage for him. It's a cave. There is standing water everywhere, and more dripping from the ceiling.
You can never completely keep the moisture out of the systems, and that means corrosion. Also, there are insects, rats and other rodents, the kind that like to chew on electrical wires and data cables. Not only do you need IT staff (constantly, every time something malfunctions) but you need exterminators working around the clock. You're asking for an infection or disease otherwise.
And that's not even talking about the everyday maintenance that would come with a facility located in a huge cave. For one, you have the bats. Thousands of bats shitting on all of your stuff all the time.
Yeah, that's guano in an attic from a couple of bats. The cleaning work would never end. Who's going to do it?
Then you have all the other moisture-related problems, like mold, and mosquitos breeding in the stagnant water. If you use pumps to keep the standing water out, then someone has to maintain the pumps. If you run massive dehumidifiers, someone has to maintain those. If you run air filters, somebody has to change the filters. And that's just the special, cave-related stuff -- you still have the routine issues with plumbing and wiring and climate control that you would get in any building, each problem requiring a contractor to go inside the Batcave without a blindfold.
So each guy, what, signs the same non-disclosure agreement as the construction workers? That's fine as long as you can threaten them with firing if they disclose anything. But what about after they leave? What's to stop them from blabbing to everyone who'll listen about their job working in Bruce Wayne's Batcave?
"You bet your ass I'm posting the blueprints on Facebook."
It's at this point you realize ...
So you have all of these people, somewhere between a few hundred and a thousand, who have signed non-disclosure agreements to not tell the world they installed the bidet in Batman's bathroom.
But why would a signed form keep somebody from blowing the lid off the operation? Sure, agencies like the CIA make contractors sign a secrecy agreement before they can walk in the door (along with a complete background check, etc) but the CIA is part of the government; they can arrest you if you leak secrets to the bad guys. Bruce Wayne has no such power. All he can do is dress up like a bat and beat the shit out of you. And by that point it's too late.
Karate is powerless against the might of Twitter.
Maybe you're thinking that since Bruce is rich, he could just buy off everybody, in exchange for their silence. But how could he outbid the competitors for that information? In The Dark Knight, they were going to pay half of all of the mob money in Gotham to the Joker to come up with a plan to expose Batman's identity. That was a pile of money as tall as a house. Two of them.
OK, maybe sheer moral obligation would keep anybody from selling out Batman to the Joker (tough to swallow, even if they are all OK with the morality behind vigilantism), but not even that matters. As of the last few minutes of The Dark Knight, most of Gotham thinks that Batman is a bad guy. So not only would they feel no need to protect him, they'd feel obligated to turn him in. The fact that there are people who would pay millions for the information is just the cherry on top. The money wouldn't have to come from the Riddler or Scarecrow -- they could just cash in on a book deal. Hell, the FBI is probably offering a reward for him by this point. And somebody among Bruce Wayne's contractors has gambling debts, or a sick mother who needs money for her medical bills.
And don't forget drug addiction!
So, there is no amount of money that Batman could pay a contractor to keep his mouth shut because someone else would always pay more. Say the mob would pay $15 million for the identity of Batman. Is Batman going to pay everyone $15,000,001 to keep quiet? $15 billion collectively? OK, how does he keep all of those transactions secret? And then what's to stop one of the laborers from taking the hush money and then ratting him out? It's not like Bruce can demand the money back from jail.
So Bale Batman is in a hell of a conundrum. What does he do with the contractors who built the Batcave? Does he just keep them down there by force, cutting off access to the outside world?
Does he kill them?
"Lucius, you can quit after I just get this cave built. It's for the greater good."
We're thinking there's literally no way to handle this problem other than to have a montage in Dark Knight Rises where Batman sneaks into the apartments of his day laborers, one at a time, and stabs them with a Batarang. Nothing else makes sense.
At this point this probably all sounds like ridiculous fanboy nitpicking, but this is actually kind of important. Remember what we said at the beginning -- the whole appeal of Batman is that he's alone, unable to share his burden with anyone truly close to him. And he manages just fine -- he's a friendless genius with no real social skills. He succeeds all by himself. That's the message of Batman. You don't need anyone if you're capable enough.
"Batman says its OK that mommy doesn't come home anymore."
But the Batcave shines a light on that ridiculous lie. Batman doesn't fight crime alone, it's physically impossible. Behind him has to be hundreds of probably poorly paid staff, many of whom go home smelling like bat shit every night, all of them bearing the same burden of secrecy that Bruce Wayne bears (if the Joker finds out you work for Batman, you and your family are dead). Only these guys don't sleep on a billionaire's mattress every night.
And they don't get the thrill of catching The Penguin or seeing their work make a difference. They just grind away, day after day, running the cables and installing the anti-virus software and rooting out the Bat-toilets.
And, of course, the Bat-Gutters.
We never see these people. They never get their moment on camera, they never get an action figure, they never win medals or get so much as a "thank you" from the people of Gotham. Even though without these nameless workers, Batman would just be some rich dipshit running blindly around town with a grappling hook, looking for crime.
Maybe that's part of the problem with the world, that all of the kids want to grow up to be Batman, but nobody wants to be the guy who takes out Batman's trash. But those people have to exist.
No one ever talks about the Bat-Proctologist.
Well, assuming Batman hasn't killed them.