My policy is, I will surrender my rig if and only if I feel that the monitoring being provided is adequate. Adequate for me means the signal is reasonably clean and clear, I can get enough volume and bottom end from the monitor, and I am getting a "more me" mix without effecting the house and everyone else's mix. If this isn't the case I am bringing my rig or I am not playing. I've had to suffer through enough horrible monitoring situations that I don't want to deal with it anymore.
I understand the plight of the sound man and I am not there to give them a hard time, but I have to be able to hear myself. If a problem arises, I just simply calmly explain that I more than capable of keeping my stage volume under control. I keep my amp facing me. If stage rumble is a problem I will raise my HPF and or put my cab on a chair.
Usually if you remain respectful nice and you know what you are talking about you can get your way with most sound men. When you get rude, which is the path many musicians take is when the sound man digs in his heels.
Funny enough I recently had a taping where I had this exact problem. The sound tech was determined for no amps on stage. Problem was the church does not have a bass player and no bass monitor. So I was supposed to be monitoring our of the house which doesn't work because in order to have a "more me" mix I have to be louder than everything coming out of the house; vocals, keys, drums, etc. This is exactly what causes volume wars, I turn up to hear myself better now someone else can't hear so they turn up and it continues and the vocalist are the ones who suffer because humans don't come equip with volume knobs. Anyway this was the end result.

