Well I think you should tell ....there is a lot of temptation..however these small things sometimes become huge problems later.
Once in a while ...it's not a big deal. I was referring to a habit ..
If I have the time, I go back right away; if I don't, I pay for it the next time I'm in.
Nope, It happens to me too on several occasions, so as long as the buzzer don't go off you're okay!
It's all about integrity. Gotta tell them they missed the water.
I would also just leave.