On a related note, would it be out of line for hunters, campers and hikers be asked to pay a SAR fee to whatever SAR group covers the area they are hunting, camping or hiking in? No fee, no rescue.
Or is that a different kind of situation, and if so, how?
They should be billed afterwards. There are always some ill prepared dimwits trying to cross the Atlantic in a kayak or whatever, and they get stranded. Canadian coast guard/navy always get stuck finding and rescuing these dumb crocs, and you can imagine how much does it cost to mobilize several naval ships and helicopters to do that each time. And of course the tax payer always get stuck paying for it.