I am probably worrying about nothing...but here goes. I'll be having an open bar where I'll be paying for all drinks at the end of the night. There is an automatic service charge of 20% added on to this (plus tax). My question is, what if my guests aren't aware of this and try to tip the bartender? Worse yet, what if the bartender has a tip jar sitting out? I guess I will just ask them to remove it if they do. The restaurant I am using does weddings often so they probably know the etiquette and I'm just worrying about nothing...