How to politely tell the bartender....

[Slacker13]

I doubt it was the bartender. I was in the business for a long time and I know bar owners around town that are known for watering down their liquor. On the other hand I have known bartenders who will sneak bottles in so they can "hook up" their regulars and not come up short on the liquor counts at the end of their shift, so I suppose it is conceivable for a bartender to conserve stock by watering yours down and pouring the good stuff for her regulars. But I would lean towards the owner.