Almost fell for it at Sheraton Arlington recently.
1 bottle was free and 2 others are not.
Ever noticed the "bad" (warm) lightning in a hotel room does not make spotting the price any easier?
Still, if I did drink it by mistake, I would leave the charge as it was not really "hidden"
I did dispute once at a Westin where I was charged multiple times for water.
Apparently the sensor was "faulty"