Nope; on the rare occasions when I solo, my route, timelines, potential sidetrack areas, etc. are left with reliable persons. Once, many years ago, I was late hitting the egress point from a trans-mountain ski journey (one of my party was grossly unable to maintain the pace). The SAR helicopter found me blasting down a pass to the egress point a day ahead of the rest; that was AFTER they picked up the fatigued person and his baby-sitter. I was 20 minutes from my egress point when they spotted me. They found us by following the annotated map I had left with my wife; it helped that the other guys moved into a clearing when they heard the helicopter laboring up thru the area, and I was carving deep tracks thru exactly where I said I would be. (I altered my route when I sped ahead and marked it on the map the other guys had; it was risky terrain, but potentially much faster.)
That incident firmly set two things in my mind:
1. Leaving trip plans with concerned persons is very effective.
2. Groups of three are not desirable (I took risks alone that I would not have taken if we had split into two groups of two - I REALLY did not want the SAR guys to have to come looking for us in the Alaska winter).
So a PLB fills in no voids for me.
Apropos of erm, nothing -- Interesting article in National Geographic Adventure magazine this month.
Tom