Hmmm - I agree with Harry - too many rules spoil the soup. Were that a rule up here, we'd merely form a new club. Using a descent ball and patch combination eliminates any chance of an 'ember' down the tube.
Seem to me, it's people who have to wipe due to fouling problems are the ones who might get chunks of cloth or other 'carp' n the bore that would hold fire. our patches are re-usable after being picked up and re-wet. When they are like that, there is no need for wiping - other than a silly rule like presented here. I understand the RULE as p[resented by Walker Mountain in this thread, but no one we shoot with, has fouling problems. The 'odd' time someoen did have fouling problems, we got that sorted out in less than a minute by chekcing their material, giving them something that is better & they are happier folks due to that - better accuracy & without a need to wipe.
Other than a rule against non-wiping, the only reason I can see to require wiping is if the ball and patch combination isn't good enough, or the bore is toast with pits - but - I've shot original guns with badly pitted bores that still didn't need wiping, but did load with some difficulty.
None of our new shooters need to wipe, and we've introduced 6 of them to black powder shooting since Christmas.