For a newbie spearo - this thread makes very interesting reading.
Crossing over from twenty years of skydiving, I can see some striking similarities between this and a computerized automatic deployment device now in current usage. The functions are reversed, the intent the same.
Falling too fast due to being knocked unconscious or losing altitude awareness - at a set height, your canopy deploys.
A major breakthrough in size and efficiency over previous AADs, the 'Cypres' cost a LOT of money. The cool and groovy high profilers started to use them - soon every newbie budgeted an extra couple thousand dollars to equip their rig with this device.
Lives started to be saved, reports of occasional early activations - but on the whole, more good things than bad.
Soon parachuting clubs started to insist on these items being used - or you could no longer jump on their dropzone. The national body in the UK insisted that they were used for anyone considering display jumping.
Regular servicing of the unit was mandatory to ensure warranted performance - and this could only be provided by licensed centres, at a cost. Out of the service period and the dropzone operator would not allow you to jump.
So, here we are today. A patented niche product for a niche market - guaranteed income stream for the manufacturer from the servicing requirement. Almost 100% takeup due to pressure from national body or jump site. The company has made a lot of money.
The similarities are clear - what is not the same is that in spearing it is still the individual who decides where and when he/she wishes to hunt. With no regulated environment restricting hunting without such a device, I fancy take-up may be be limited.
I think it is a great idea and will certainly be looking at purchase when they hit the shelves.
Rgds Ian