Personally, Mine does hang in the bathroom. (next to the sink) I have a fairly powerful ventilation fan and humidity stays very low. Sure there are a few water spots on the leather,(from splashover) but meh...
I do agree though that high and constant humidity will cause leather to cup. That's definitely bad for strops. In the end it comes down to your own personal situation. I like to keep my gear in a single centralized location, minus the stones!