Not sure what you're referring to exactly, but the local one has four people sitting at a table handing out registration cards, which are also a draw for some sort of prize I guess as an incentive for people to register. It takes seconds to register. I wasn't counting, but there must have been at least 3-400 people go in, locally, with just as many supporters on shore. I'm guessing most places must run it similarly, but I suppose that doesn't count anyone who "chickens out" after registering.

My 5 y.o. went in for the first time, and my 7 y.o. went in all the way for a high five from the search and rescue team that's out in shoulder-deep water in dry suits. (I helped her in the deeper water, for speed's sake).

It's a great tradition, and very well attended. The parking lot is completely full 20-minutes before the start time.