Re: bait and switch sign up
Morrisons supermarket took it one step further, by letting me register firstname.lastname@example.org, but then refusing to let me log in with it. I gave up on them.
A rarer favourite of web coders who have grown bored of "you failed my validation but if I tell you hwo I'll have to klill you" is to accept an overlong password value and simply truncate it to the length they were anticipating before creating your account. Similar fun can be had with the username. Those super secure password/unique email wonks don't like it up 'em.