[twright0]

There's not a lot of black hat activity, but there's plenty of good- to neutral-natured messing about. The "Wall of Sheep" is a great example; if you send something that looks like a username/password on the public wifi, someone will put it up on a big display (though they'll obscure some of the password field) along with the other 'sheep'. Not "black hat" but definitely not the kind of thing you want on a real account.

As for burner clothes, the only thing I've ever heard is to not wear company-branded clothes - wearing an obvious Google t-shirt is a great way to attract attention you may not want.

[Natsu]

Speaking of which, I've long wondered how hard it would be to make the wall of sheep display ASCII art or something by letting it sniff bogus credentials....

[boha]

A human reviews every submission before it goes on the wall. We might notice; we might not. ;)

[Natsu]

The idea is out there now. Might have to be more vigilant :)