Its never good to be overworked, your productivity tends to drop when you're tired so in my opinion it should be avoided unless you absolutely have to meet a deadline for some reason.
But still I think that many (maybe the most) of the people in this field (hardcore game programming ) Is 'overworked often' Or am I wrong and most of them is relaxed and 'at ease' when working ?
Some crunch time is virtually unavoidable when you're working with big projects and deadlines though. (and during crunchtime almost everyone will be overworked)
How often it happens depends on the company. If it happens often it is a sign of bad management (I don't think bad management is more common in the games industry than in other industries)