Gary, my bride wants me to get two of those for my twin 45's, our grandkids frequently ride up on the bow, legs around the bow pulpit. I don't see how they could possibly fall off but can't completely discount it. They wear life jackets, of course, and I think if they took a tumble, however unlikely that may be, they'd get thrown outside the wake/propwash area by the bow wave.
I'm sure lots of you will come back and tell me I shouldn't let them do that at all. You're right. Hard to tell a 10 year old that he/she isn't invincible....The ring prop might help my bride's feelings and my guilty complex as well...
Charlie