Actually this one is easy to answer because Willow learned about Buffy being a criminal this very second. While she's been keeping Kennedy away for a year.

There could be similar incidents on a lesser scale.

As for playing for laughs: if there's one guy who was treated seriously as a nasty, nasty person that would be Warren. Buffy got compared to Warren. That one Joss would never laugh off.

I've just read the transcript of the latest Brian Lynch's podcast. Here's his estimation of Buffy's bank robbery: "It's not the right thing that she's doing, but it's not a terrible thing that's she's doing".

This is the opinion of a person who works closely to Joss. ::shrugs::