I had this idea on board retrieval, whether it's a good idea or not is yet to be seen, and so I put it out there for scrutiny.
The current solutions that I know of are:
1.) Board leashes / Reel Leash
2.) Inflatable GoJoe
So board leashes are dangerous as they have the potential to create tension in the line and snapping the board back in your general direction, more specifically your face neck and head. GoJoe is a more suitable option but you look like a complete twonk and it's not always convenient to have an inflatable cushion between your legs.
So why not take the best of both and combine it into one product?
My idea was to set up a reel leash to a release mechanism so when the line reaches enough tension it pulls the pin to a gas canister which inflates a visible balloon making it easier to find your board after a big stack, I thought if the leash line was long enough or the tension in the line wasn't high enough to rip the board from the water then the line would stay connected and you could pull the board back in, if the crash was big enough or the line came under too much tension then the pin would be pulled and the balloon would inflate allowing you time to recover and locate your board which would hopefully be easier to find.
I had a crack at sketching up how I thought it would work