I had a bladder in a FastBack Systems Double Century on my Volae and I was pretty sure that the hose would end up in the back wheel sooner or later. I was pretty attentive to its location, but you can't spend all your time checking on your hose. I sold the bike, but if I had kept it I was going to figure out a way to route the hose so that it wouldn't fall into the rear wheel if it came up attached.

I actually prefer bottles so on my Fujin I'm using the FBS bag to hold my gear and putting fluids in bottle holders - works better for me.