Out of interest I watched the start of 07 race (youtube) and couldn't believe my eyes regarding the start boat - has anyone ever been run over by it as it's appears a very fine line between the nose of your board hitting the outboard or mistiming and landing in the boat. Crazy French!!!!
Last year, top-racer Pieter Bijl mis-timed his start by a split-second, and hit the side of the rabbit-boat, ending in a (harmless) catapult. He still managed to finish top-5 or so that manche, and second overall.

BTW, as a general recall is pretty difficult with hundreds of riders, at the skippers it is emphasized very strongly that everybody stays behind the starting line till the boat has passed, at the risk of being disqualified "for life" from the Defi, or worse... being driven over by the start boat. After every manche a few names of "offenders" (=early starters) are throw in the masses, so to discourage even more people from doing so.
Since 2006, they have a really powerfull & fast starting boat, so the +-500m starting line gets cleared in less then 30sec... which is quite neglectable compared to the differences at the finish-line. But, to be honest, most top-guys do start at the downwind pin-end for earliest release.
About the starting sequence: there is a count-down of 60min initiated during the skippersmeeting (held before every manche), which the race director (in his starting boat) sticks to pretty accurately. So still plenty of time to go and try to find your own set, between the 1000+ sails on the beach (most people have at least 2 sails rigged). Quite a sight!
Speeking here from my personal 2006 & 2007 participation. This year, unfortunately (or by now: luckily!?), I could not attend (eventhough I was subscribed).
I hope to be there again next year!