I think that with both skiing and cricket (mentioned by Klaus) the main danger is from an accidental collision rather than what would automatically happen doing the activity.

I agree with Klaus on that. I once had a pretty strong clash of heads when two people were going to take the same catch. The trouble is with that is that you are both looking upwards and running to the same spot from opposite directions. If I were going to play cricket again I would be very careful to look around me if I were going to try to catch a high ball. Looking around you is a good way to miss it, but the lesser of two evils. You do also have to be careful of collisions running between the wickets also.

But you can't plan for everything and it's the unplanned events that are the most dangerous, like colliding with a dare-devil snowboarder who isn't paying attention.

CS

Yeah I guess the main question is, would I have sufficient awareness/willpower/fear to take my eye off the ball and look around if I was going for a catch when there was a danger of a collision. Similarly when batting prioritising not crashing into someone over trying to avoid being run out. If the answers are yes then I think the risk of concussion would be very low, as I could avoid fielding too close and getting hit that way. I guess it depends on how much I can curb that competitive instinct!

This isn't something I'm even going to consider for at least 2 years but it would be great not to have to give up sport altogether forever.