Today I hook on accidentally whilst trying a fancy (for me) gibe on my Goya.
The deep gash on the quad hurts like hell.
Question is: how often do you hook on accidentally, or is it me only? Seems to happen too often here, as in one bad one every 4-5 outings...
Not often, but always at the worst possible time.
I've caught the uphaul more often than the harness lines, which is why I rarely put one on.
Only in really marginal conditions where I might get totally becalmed.
Yep the point of no return on the gybe and you find you are going with the sail like it or not. 
i get it when i run into a lul with a realy high boom and short harness lines .. trying to jump out of them before going in backwards
Yep..after a wipeout like that Im super aware for a while & even tired to push the lines away with my fingers as I initiate a turn.
solution
as you start to enter a gybe, move front hand back to the lines, and use your thumb to push the lines away from yourself
added benefit is it makes it easier to lean the mast forward and oversheet as you enter the gybe, thus keeping the nose down and engaging more rail
Is it worth me noting that all these wipe-outs are much worse than any attempt at a forward loop ?
Huh, I was doing a 360 gybe, hands are far back for this move.
But yeah, next time I'll "think" more about what I'm doing. 
too often is the answer (once is one too many 
) For me its most often when Im at my most relaxed that the hook unexpectadly catches the line - not more than twice a year but most annoying.
a friend sailing down sandy point a few years ago came in after a marathon session. he said that as he came into the shallow he unhooked and de-powered. he was so tired he let go of the sail to let it fall leeward, intending to fall windward into the water himself. not quite sure on the details here, but somehow the harness re-engaged, and violently threw him over the handlebars with the sail. the sail pile drives him and he dislocates his shoulder.
untangling himself, with his good arm he tries to wave down his brother who is still blasting out the back. bro' waves happily back and continues blasting...
correct any details I got wrong Sam. :)
Easy fix, learn to sail with the hook up, no more accidental hook ups during a gybe. Also very useful while wave sailing, bottom turns are a real bitch when your hook grabs a line half way through.
Only happens to me when doing a light wind flare gybe and just about to flip the rig when sailing clew first. I usually glance down to check now (too many of these )
Used to happen to me often at the start of the gybe especially on a windy day and very bumpy swell where my harness lines would flail about...days before plastic covers over the lines. Nowadays I wish I could find time to sail when it's windy to see if it still happens, long way to go for that to happen me thinks.
Got a 7.5 sail now, just have to try it out....baby steps to being a real windsurfer again! Slow progress but getting there! Watch this space!
There are days when I re-hook in during every third or fourth jibe. Then months go by with no problem. I'm in a no-problem stretch now...
JINXED IT!
Invariably it's a bent front elbow that causes the problem.
(all of this excludes the classic "catapult to under-sail, hooked in, inside the boom" freestyle explosion).
Only hook in accidentally when I'm in the middle of a perfect planing gybe! 
So then it ends up being not so perfect after the face plant.
Half way through the gybe, watching where I'm going...seems to be a pattern forming here
I'm with Airsail, hook up.
When I got a new harness I started to occasionally hook in unintentionally, I think because the new hooks are long and curve a long way back, trapping the harness line, unlike my old short hook. So I thought "maybe there's a good reason nearly everyone goes hook down these days" and persevered for a session or two hook down but I kept hooking in on gybes and I wasn't going to alter my gybes because of my harness. Same as you shouldn't have to hold the line with your hand to keep it out of the way in a gybe. So I went back to hook up, and if I shorten the hook (by welding) it'll be even better.
The other side of the issue is how easy is it to unhook in a hurry, which can be shown by how often you catapult hooked in. For me almost never, once every few years at most.
could it be that those getting hooked in are not leaning forward enough, extending the front arm and driving therail through the gybe?
i'm certainly no expert technician but i've never gotten hooked in by accident. to be honest i just can't see how it's possible unless your wave sailing.
