I think the signature of those kinds of fake accounts are different than most of the malicious accounts though.

You creating a fake college account and forgetting about it probably passes as human enough, there's no concerted effort or agenda to that account besides existing and adding friends at your college.

I think what makes bots and fake accounts generally detectable is consistently pushing certain messages in ways that exceed normal human behavior, as well as showing patterns across many fake accounts.

It's hard to see a pattern in one fake account, but easy to spot it across many.