JW, I completely understand your comment. I shoot 26" draw and I wouldn't want someone pulling one of my bows 31". But with a group of experience bowyers, I wouldn't have much a problem trusting them not to over draw me bow. But, I'd probably still put a rubber band around my arrow for them as a reminder. Still this type of shoot would not be everyone's cup of tea. And I respect that.
I relate asking someone if I can shoot their bow to asking someone if I can take their Harley for spin? It's a very personal thing.
With the right bunch of folks this could be a fun outing, though.