Mate with a leash the board will catapult right back at ya
imagine a good fast lofting traveling downwind at speed with a board
flailing behind you cause its leashed to you
you will stop faster than it does when you hit the water
IMO loosing a board is far better than your head/neck/back whatever
loosing your board hurts

but a board wedged in the back of you
somwhere will probably hurt lots more