A thread at Google Groups mentions a climber at Big Bend National Park summoning rescuers because he was stuck on a rock.
I know the boys at GoBlog are opposed to this sort of thing on general principles — it’s not exactly manly to call in a rescue unless the need is absolutely dire (in which case you might be in no condition to summon your next breath, much less a search-and-extraction team).
I can see where these locator beacons can be a good thing when hardly anybody uses them, but if like all technologies they get cheap and ubiquitous, do they become the equivalent of the car alarm keeping the neighborhood up all night?
I consider PLB’s inadequate for most people because they don’t provide any way to communicate anything except “Help!”, and your location. You can’t report the severity of your situation, you can’t report what your rescue needs are, and you don’t get any response or acknowledgement. That’s a long list of problems that are going to add up to lots of assumptions having to be made on both ends of the situation, and a lack of adequate communication in general.
I suppose if I were going into somewhere particularly remote, it might be a useful additional piece of safety gear. But it’s no substitute for a well documented and widely disseminated plan (let someone know where you’re going and when to expect you), and then in more isolated locations some kind of two-way communication (something that I’ve research to know will work from my location). It’s important that the people who know your plan and who are likely to be the first to report you missing also know, in detail, what that communication gear is you have with you, and how you plan to use it. That kind of information is invaluable to search and rescue folks.
It’s interesting to note that Amateur Radio, still one of the most effective communication tools for remote communications from anywhere (in the hands of someone who knows what they’re doing), has just become easier to qualify for. The laws have now changed eliminating the requirement for Morse Code as of the beginning of this year.