So, once convinced that some of the basic Santa plausibility obstacles can be overcome with technology, little Timmy may get it in his head that he's going secretly YouTube that Santa shit and get famous. That is, if he doesn't ask why none of the world's children have ever sneaked downstairs on Christmas Eve and caught Santa in the act before now ...
Most kids don't have the stomach for a real trap.
So How Does Santa Do it?
No one can see Santa because he's wearing an invisibility cloak.
It's not magical. Thanks to a brand new technology called metamaterials, scientists are figuring out a way to bend light around objects, which essentially renders them invisible. What you really end up with is a light-bending metamaterial suit that is a little more Predator than Harry Potter, but close enough. Plus, Santa could similarly bend other forms of electromagnetic radiation around himself, meaning he could easily hide form infrared and laser sensors as well.
And even if a kid does get past Santa's defenses and catch the bearded man cramming an Xbox Kinect under the tree, he certainly won't remember it when he wakes up. Scientists already have theorized about how specific memories can be removed from the brain, Men in Black style, by using drugs to eliminate certain proteins. Children who resist such treatment are, of course, killed.
"I need full clean-up at #447."
Let's say you have an especially savvy and worldly kid, one who reads the news. Is he truly to believe that in this post-9/11 world, where any stray private aircraft can cause half a dozen fighter jets to be scrambled in response, nobody would raise an eyebrow at a small craft zipping around the world at impossible speeds? We honestly let this guy fly right over the freaking White House without a dozen air-to-air missiles turning him into a huge fireball that stinks of reindeer fur?
It's just a good thing the Russians don't believe in Christmas.
So How Does Santa Do it?
Uh, we hate to break it to you, cynical hypothetical child, but The North American Aerospace Defense Command totally tracks Santa. It's a yearly tradition that the same folks once tasked with monitoring the skies for incoming Soviet nukes use their state of the art missile and aircraft tracking systems to keep up with St. Nick.
How do they do it? Well, according to their website, "NORAD uses four high-tech systems to track Santa -- radar, satellites, Santa Cams and fighter jets."
They did their job when the Tooth Fairy went rogue, too.
And if the somewhat esoteric description of a military installation tracking Mr. Claus doesn't do the trick, show them his progress on Google Earth. That's right, the most powerful military on Earth has teamed up with one of the world's largest corporations to state that unequivocally Santa does exist. And as we all know, anyone endorsed by the United States government is legally a real thing. What more do you want from us?