I was gritting my teeth a lot during the episode, too. Even without a patch, the ball rolling out of a fouled barrel made me wonder just how undersize the ball was. Shooting unpatched ball does have some historical basis at close range when speed in loading is more important than max accuracy.
I suspect the patch was omitted to keep the contestants from having to learn another step in an unfamiliar loading process, and to allow for rapidly clearing a problem had a contestant dry-balled his load. To have added the patching (which at 10 yards wasn't necessary for accuracy), they perhaps would have needed a short starter, a better loading rod, and maybe a loading stand. Still, if I were setting up the challenge, I'd have started with a packet of .005 prelubed, precut patches.
Wonder how the show would have handled a broken or loose flint, or a flash in the pan? I like Top Shot for the photography and slow motion view of the guns and bullets in flight, but they seem clueless about muzzleloaders.