I eventually did go to Kitsilano Beach with my hosiery under my shorts. I wore them the entire time. I stayed for about 4 - 5 hours. Nothing bad happened. If anything, I was the person causing the trouble. ;^)
I'm still not sure that I would wear them in the water, though. For those of you who wonder about whether normal people do swim with hosiery: Western Mass, States, Banquet '05. There are more, but those are the only photos that I could find.