In my current position, if I'm caught working unpaid voluntary overtime, I will be told to leave. If I am caught working overtime again, I will be fired. That is what I was told by both my superior and my professional association... and I know people who've been terminated for being busted doing VOT. So it's a YMMV. Although, I can work overtime and get paid for it. So, it probably varies by department and implementation... I don't even think your method solves the blackberry problem. When they ask you to do something in the middle of the night, you didn't volunteer.