Overtime, by definition, is still time on the clock, and voluntarily staying to work that time doesn't automatically mean that your employer is now a charity. You can't just “volunteer” for your employer. The very premise itself is silly. Sure, if you're on a salary that is exempt from overtime pay, you'll probably have to work some extra hours during times of high workload, but it's expected that, in turn, during times when there is less work to be done you'll still get paid your full salary.…