I agree that it should be declared in advance so that you can't play to the conditions. I also think that it's very much in the spirit of F16. If this was F18, I'd be stuffed because Ann simply can't get that Friday off (I always understood that teachers could just throw sickies for this kind of thing, but apparently not...) Sailing F16 means sailing more.

Of course, with most events not requiring pre-registration, you're always free to dump/gain a crew up till the day of the event, provided that you stick with the decision for the rest of the event.

Paul