"When did I ever say anything about allergic reactions? I specifically said poisonous not allergic. FYI, epi pens do not work for venomous bites."
Perhaps there is confusion here since your OP mentioned "poisonous bites/stings." I think he might be wondering which typical poisonous "stings" would require a PLB-based emergency evac. Typically that is going to be caused by a severe allergic reaction, which the Epipen is for (I imagine he doesn't think it's for poisonous bites). I can't think of other stings which would require a PLB for in California, except perhaps Africanized bees or something like that. An envenomated snakebite that is showing effects is a different matter I imagine, and definitely means getting out to see help, if not by foot, car, or horse-drawn buggy, then by PLB-called helicoper.
For me, I don't see much of a need for a PLB for lots of hiking, but I do think about the value of it when doing longer, solo cross-country hiking, where something like a broken ankle could make things really dangerous.
There are always going to be people calling for rescue when they don't need it (via smoke signal, Aldis lamp, cell phone, PLB) and I'm glad there are people around that will risk their lives to try to help people. But I also do agree that GPS, cell phones, and PLBs tend to embolden folks to do things they might not otherwise have the experience to try, and perhaps fail at. I guess part of this is that folks might not feel the need for the most basic planning, such as checking weather forecasts, leaving detailed itinerary info/maps, and the like. "If it goes bad, I'll just call for help!"