lol there's not all that much issues with a non motorized vehicle. If you are drinking to the point that you are doing dangerous things in a non motorized vehicle chances are you would be doing dangerous things regardless of what setting you're in. I'd say operating a camp fire while drunk is probably more dangerous than a canoe or pedal boat on an open lake. Unless you are drunk to the point that you decide to have a camp fire inside the canoe. 😛
This is not about being pissed drunk, that's stupid regardless. This is about having a few drinks. That will do zero harm. Not to mention that in a typical canoing setting there is nothing or no one around to even be a danger towards unless you really suck at picking good camping spots. Me personally I don't tend to drink when on the water as that tends to involve being in direct sun light, so if I'll drink anything it will probably be water, but I also believe in freedom.