Yes,
it seems there can always be a downside (sic

) to most actions. So while painters can be a big risk, they also can be extremely useful. While creek'n and especially on exploratory runs I always make sure to attach at least one long beefy painter. While everyone else is (up in the poison ivy) hiking, bush whacking, and boulder hopping, I've lowered down 10-15-20 feet at a time and scouted that next drop. Remember that includes boat length. Often I'll lower that first drop onto rock, and boat the rest of a drop... that others can't get to. Or lower one side, step in ferry across, then lower drop on other side. Canoe's can very often out-pace their deck-ed brethren in this manner. With a good length painter you can also loop a tree, and walk down a canoe like a ladder...(yes u can throw rope it)... this alone can get you invited back, when with a new crew. And the ability to grab a painter, get away from a loaded boat, and to a rock is a mighty big plus... you can even swim to the other side of rock from your boat, and let the painter grab it. The ability to self rescue, will not only help get you included back, it also helps keep from placing others in harms way. Don't they teach securing any rope in like 'Canoeing 101' or the prerequisite 'Intro to Whitewater' ?
I've seen air-bag lacing that scared me more.
On less demanding or other type runs, I always double loop a prussic around my waist with a self-locking parabiner, and forgo the painter. This allows for a quick get to and attachment.... and I can keep the loop in my lower hand while stroking (like Tommy said in orig post), and can let go immediately or at that last moment (another good reason, to be able to paddle on both sides). I find this really nice, as when the load starts getting tough - you can pull/jerk the boat forward, then stroke, and again, and again. And having that extra length of reach with you all the time, can be a life saver for you, as well as someone else. Especially when coupled with a paddle. As already mentioned, that dope-on-a-rope PFD is on the wish list... but (like also said), I can't imagine ever using one to tow a boat around.
As for the Craig
boat-up post

I've not read his complete list of reasons... but often if there's a lot of trapped air under a overturned boat, it's way beneficial to keep it there. In this manner (if floating high) they seem much easier to push around (IMHO), and can also be mighty nice to climb up on it a pinch (again IMHO)

. You want to get cursed quick, flip my floating high boat over.. and you'll think twice next time. In fact I'll often grab the end of a full kayak... lift.. pour some water out... leave turned over... and fling it forward into a ferry angle. And Yes - a full canoe upside down sucks, as the ends grab, and the decks get pulled off, and the gunwales seem to lodge everywhere, and they weigh tons.