You seem to have dramatically misunderstood what I said, then. At no point am I talking about pure happenstance - none of this is accidental in those terms. It's people attempting something and messing up badly.

Almost every contact sport has the equivalent of attempting something legal but messing it up so badly it ends up illegal, dangerous, and resulting in a red card or equivalent. It's a lot more common than deliberate foul play - and me not listing them exhaustively is because it's self evident!

Is a brain injury worth getting an advantage in a game? I'd guess for most players, no.

Sexton was trying to get one of ours carded...was it Willis?

thought it looked like FS was running in to try to kick the ball but pulled out and tried to turn when he knew he couldnt get there hence turning sideways and hence he was moving forward until just prior to the collision. It was a yellow not a red, both entitled to go for the ball, no attempt at a tackle and an attempt to turn out the way with an unlucky head injury the result.