You don't have to refuse to do overtime. Just take a comparable amount of time off. One of the things about salary vs. hourly is (at least the way I used to tr

You don't have to refuse to do overtime. Just take a comparable amount of time off. 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.