A google search has been sufficient before. Remember the pressure cooker and backpacks search from a family in New York?

A Google search was not sufficient in that case. The guy's employer tipped them off after firing him - it wasn't some sort of automated keyword monitoring at Google.

https://www.theatlantic.com/national/archive/2013/08/governm...

The search alone wasn't sufficient, but was enough to start it all. In YouTube's cases, there are plenty of comments that demonstrate someone is a sexual predator. In my view, if someone "tipped them off", it would be the exact same scenario.

"A random person on the internet is posting creepy comments" is likely not probable cause, especially as you'd have to convince someone national like the FBI to care without a specific location.

"Someone I know personally is posting creepy comments, and I've always gotten a bad vibe about their interactions with kids" is probably enough to get local cops interested enough to knock on a door.

I hope not. Unless there is evidence of a crime that has occurred or evidence that a crime is planned, they have no business (constitutionally) bothering a citizen based on that kind of tip. This is how lives are ruined when there are no victims.