I'm currently staying at the Conrad London St. James. It's also about 100F/40C here in London today. I went into the lounge, grabbed a bottle of still water, took a sip, and started to leave. I was stopped at the door by a lounge agent who said I cannot do that. I could have easily fit the bottle in my pocket and she'd have never known, but I thought this was such a trivial item to "steal" that it wouldn't really make a difference, especially given the weather. I didn't argue with her, but I also didn't feel compelled to apologize so I just set the bottle on the table near the door and left.

Am I really being that awful stealing 75% of a bottle of water? They had beer, sodas, and other items which I did not take.