My problem with this is if you HAD to stop somewhere and go inside what do you do with the handgun?
That, and the fact that my seat bag has tools, spare tube, etc. Would rather not have to take my gun out of the bag when I'm fixing a flat. Awkward. And on charity rides, etc. it's pretty normal to set your bike down while you visit the porta-potty and refreshment tent. Rather have it on me.