I am grateful that we have SAR teams...even if I've never called in myself. I've heard of plenty of well prepared people that needed a rescue (usually because of an injury). and, even if they did charge per rescue, you'd still get the boneheads that call in 'because they don't like the water'. I'm definitely planning on getting a SPOT II for my trip (High Sierra Trail) in 2015. Those of us that know what we're getting into don't push the button willy-nilly. But when we do push the button, please come running...I promise it won't be a waste of time.
I got a PLB. Stronger signal, and no question about it in the minds of folks who have my itinerary. SPOT devices that are supposed to send signals to let folks know OK and then do not get the signal through leave family members panicking that the SPOT is sitting there not moving for days... And they forgot it on a rock. Or it got picked up by another hiker and has been moving in the other direction.... on another forum, this was an issue for a few days - the family got messages texted to them by someone who was obviously not "dad".
My PLB is in a secure place and my fellow group members know where it is in case I am incapacitated, and not to use it unless there is no chance of getting us back out of the wilderness without help. It'll last for five years, at which point I'll replace the battery as scheduled, and it has no subscription fees.
If you read the wilderness guide published on the sequoia-kings canyon website, there's a paragraph that emphatically states not to rely on electronic signaling devices - this is an indicator that no one should pretend that they replace the oft-repeated request that you leave an itinerary with someone who will call for help if you don't return by a specified time. The vast majority of backpackers don't ever call, but the odds are sometimes not in your favor so it's always a good idea...
I wouldn't want to require that people carry the devices. Some chafe at the notion that they should leave an itinerary... I can only imagine the yowling and howling that they be forced to haul some electric gadget along "for no reason."