Or do what Chadd did a few yrs back now, bring two bottles to a session. One with regular water that you hide and your usual bottle with straight Vodka in it. Some dumbarse will come off, have a squeeze and learn their lesson one way or another. Lemon juice in the water is my preferred method of dealing with those people. It's no big deal if you're expecting it but a rude shock otherwise. Even better for those guys that use a bottle instead of a shower. I keep my mouthguard in the bottle before and after playing. Most regulars know I do this, but every once in a while somebody takes a squirt with he bench letting them know about it afterwards. I've realized that if you bring a sports drink (e.g. gatorade, powerade, etc) people are less likely to help themselves