I just got a Topeak Road morph. I was considering alternate locations other than the top tube to mount the pump. Is there any reason why I would not want to consider mounting it to the outer edge of my Fork? I figure it's not much different than front panniers.

The frame of my bike isn't very large, so having a pump under the top tube interferes w/ using the water bottles sometimes, and since I have to carry my bike up stairs everyday at work, it would just be easier to have the pump located somewhere else.