Until recently, I would have agreed that almost all SARs I've heard about or been involved in were legit. Maybe not ultimately requiring the response (e.g. a helicopter or something else expensive) but some level of agency response was needed.
When cell phones came into use, I was worried we'd get more bogus requests but they actually helped define the problem and make an appropriate response -- you could usually talk to the party and tell them to wait or struggle down on their own.
SPOTs & PLBs,though, might be a problem. You don't have that two way communication. All you have is something that supposedly says "Help." The SPOT & PLB calls this year at Sequoia Kings were almost all bogus. Calls for help by people who didn't even bother coming up with a Plan II for self-evacuation. Then there was also a techno-related case of a party following their GPS without any regard for the terrain it was taking them into. That ultimately required a major search effort and short-haul helicopter rescue of three people.
So that's to say that the taxpayer cost of people not using their technology in a responsible way may be increasing. At the moment, I don't advocate charging for rescues, but I'd sure want to start looking at whether a call is legit as well as at how the companies market their gizmos and what sort of instructions and form factor they have that prevents bogus calls. They're the ones profiting from these things. Maybe they're the ones who should cover some of the SAR costs when not justified.
George