On my 74 90/6 I always have that same problem with the starter button hitting the tank bag when the engine is running. possibly one of the reasons why my starter motor needs attention...
I too am wondering what to do about this on the G/S. I've removed all of that starting only with clutch in or in neutral junk. One thought was to have a simple switch to enable and disable the starter button, kinda silly and redundant though. The other was like Charlie's idea to have a separate starter button that is more out of the way for the starter and then use the old starter button for another purpose.
Not sure what though.
An extra horn seems like the leading option- but the only way I could justify it was if it was an actual EXTRA horn, you know, a really ear piercing loud one. Fire the left for friendly noises, and fire the right for fending off cars trying to kill me, and fire both for special occasions, like saying farewell to people early in the morning. At least with two horn buttons I might actually hit the right one more often

I don't know. Suggestions? Maybe we need our own thread.
I've also gotta find a neat, small and simple and durable killswitch- one that opens the circuit when pressed (I have the wires ready to stick this switch between).