<-- Currently making around 30k/yr with exempt status. Though my position doesn't usually demand OT, near release (Software QA) I've had to put in anywhere from 5-10 hours unpaid OT those weeks.
I'm not happy about it. But there isn't much I can do right now, I'm fairly confident I'd be let go if I point blank refused to do any OT. I'm unfortunately in a very expendable position at my company.
One of the things about salary vs. hourly is (at least the way I used to treat it as an employer) is that a salary employee could take off in the morning for a doctors appointment and they still received the same pay. Or for actually anything. Not so with hourly. Although a passive aggressive way to equalize the situation, it might make more sense than drawing a line in the sand. You could also try to re-negotiate your "salary" to take into account the extra work.
Unfortunately, if I'm not at work anytime between 8AM-5PM, it's going to go down as either sick or vacation/holiday. No free time around here.
But I understand this isn't the norm, I know my company is in the extreme bad side of this debate.