Has nothing to do with unions, but reminded me of something that happened when I was younger. I was waiting tables at this restaurant and I had only been there a couple of months. I hated the GM as he was a complete dick so was considering moving on to another restaurant. Well, as a waiter making 2.12 an hour and paying for the employee meal plan on top of that, I didn't pay much attention to my paycheck. I worked close to 40 hours a weeks so I would get a 2 week check of maybe 20 dollars. Well, I got one check that was zeroed out, then a second. I wasn't really paying attention the first time, figured I made too much in tips. I went back and looked though and in each two week period, it claimed I worked around 36 hours.
Long story short (too late): The manager was shaving my hours (and others). I asked for my time worked for each day and my tips claimed when he was away at the GM conference in Hawaii. I had one night where supposedly I worked an hour and a half and claimed $100 in tips. Keep in mind, it took 30 minutes to do sidework, before I could leave.
I confronted him with it when he got back. He paid me $100.00 out of the bar drawer. That was Steak and Ale btw, some of you may recognize it. It was a fairly big chain.