I'm thinking of the scenario when the rider runs into something, but the angle isnt there for an endo, so the bike just stops cold in its tracks, and the rider goes down and forward hard. The same result might occur if he or she blows a pedal or breaks a chain.

Not to say there wouldn't be injury if the tube were cut, but a 1.125 x 3" cylinder to the solar plexus, chin, or teeth is in this case an avoidable situation.