Common enough. Same with slaughtering captured prisoners, murder and similar.
They write down Good, and then start acting very Evil. When called out on it, they provide a ton of justifications.
Personally, I dont tolerate that crap. I'll explain my take on alignments, how they're viewed by the 'Gods' and that's that. I'll indicate to a new player if I think he's stepping outside his alignment and eventually I'll note the PC's actual alignment on my own records, and if there is a game effect that triggers on alignment (a unicorns lair, a talisman of ultimate evil etc) then it works off the alignment they've been playing, not what is written on their character sheet.