The last place I worked QA was on a deadline and the team for one product had their vacations cancelled. After the HR rep heard about it and went ballistic someone else was asked multiple times to cancel a vacation so she could participate in a conference that happened to be the same place she and her kids were going. Somehow them paying for her plain tickets didn't make up for the time she would need to be working so she refused. Fortunately by both having a great boss and insisting on only working critical issues off-hours I mostly avoided a lot of overtime. Even with the critical issues we got paid for being on pager.

My current place I'm doing some more overtime but that's mostly due to the fact I'm the only DBA so there are times it's needed to keep things running. Since I'm given comp time (sometimes without even asking for it) it doesn't work out to be much overtime though.