Earlier quoted context omitted.
> How difficult was it to not suspect it anymore? Excellent observation. It's really about people conditioned to follow scripts. These people were missing the "de-escalation script" in which a teacher laughs, puts their hand on their forehead and says, "Wow, That scared the shit out of me for a minute there. Now let's show you how to make a tidy wooden box for your amazing clock project."
Well I guess they could logically suspect that he might be doing something more sinister than just bringing around a clock project. So fine get a court order to search his house while keeping him detained at school. Find nothing. Apologize and let him go.
Didn't treat the clock like a bomb? Might get fired. Did treat it like a bomb, turned out to be wrong, apologized? Might get fired. Did treat it like a bomb, turned out to be wrong, uhhh... maybe if I get the police involved I can make this not my fault?
Reasonable errors on all levels are often greeted with harsh punishment and sometimes demonization by news media. It's not just kids who are subject to it. People are rightly terrified of being blamed for errors that anyone could make, and their behavior makes a lot of sense in that context.