Good point, I understand Andrew. All I really meant to say is, everything in the "system" is vulnerable. And, after reading some of the responses, there can be surprises, so this is a great thread.
As for the Optis... It's not the 30 Optis that you have to worry about, or even the 4-5 RC boats. It's the 20 coach/parent boats... Of course, with all those power boats available, surely someone offered to tow you in?

As someone who runs a lot of kid events, including Optis, I'm very surprised they wouldn't be taking them under tow through a narrow pass, especially with heavy current.
I can also tell you that we tend to be very protective of our racing circles, and you'd be amazed at what morons will do to a race course. "Look at all the cute boats..."
Mike