I dunno about that correlation, water fountains are offered freely by those who are paying for the water to any passerby. This question is more of a moralistic question in "how would you feel about yourself afterwards."
A better response question similar yours would be like "If a house you visited had a bottle of 1991 red wine (whatever brand), would you drink 2/3rd's of it and leave the rest for them?"
I don't know too much about wine so just bare with me and assume it's an expensive wine.
Also don't assume I feel that you should feel bad about raiding a level 10 manor. I just wanted to offer up a better response question to represent this question. Technically you are stealing something expensive (a lvl 10 manor collection) from someone. Do I think you should feel bad about that? No because that's what this game is, a competitive PvP game with quests involved