That was the actual argument, despite the fact that such a scenario has never, ever actually happened, and never will (bombs don't work that way). And, once you buy into it, it'll be about five seconds before they say, "And if you think about it, isn't selling marijuana a form of terrorism? And isn't all of society a kind of a ticking time bomb, at all times?"
This playbook has been used to justify centuries of bullshit, because it always works. "Give people the right to immigrate to the USA? What if one of them turns out to be TERRORIST and they SET OFF A NUKE?" "You want people to have a right to privacy? What if they use their privacy to BUILD A NUKE?" "You want people to have freedom of speech? What if they use that speech to RADICALIZE TERRORISTS who then BUILD A NUKE?"
I think that reasoning is dangerous as hell, whether the supposed terrorist you're talking about is a member of ISIS, a Nazi, or QAnon. Their trick is to make it seem like any argument for due process or privacy is really an argument for terrorists destroying cities, as if the extreme scenario is the only one worth talking about. In practice, it winds up being used as a justification to ruin the lives of people who A) wouldn't actually bomb anyone, even if they knew how to, and B) don't have enough money or influence to fight back.