"It was my understanding that the search for Ken started when those not on the trail noticed that he missed a plane trip back to MI."
I believe some news reports confirm my comment. Check the string carefully.
"I maintain that they are unnecessary. They are unreliable in the sense that when the battery goes, it's useless, not that they are inaccurate in their readings."
I think John Shannon and Bruce Nelson have responded to this old canard. Fresh batteries can last 17 hours in use. You need not have your GPS on at all times. You can carry extra Lithium batteries. They work in your SPOT as well. They are better in cold weather too.
"I maintain that you will simply run out of battery power on trips longer than an overnighter if you keep it on. I also think that it's a poor substitute for a locator beacon if that's what you really want."
If your cell phone is out of tower range, turn it off for goodness sake. "Coupled with a GPS, a cell phone takes the search out of SAR"
"Maybe I'm wrong here. Does a good deal of SAR occur at night? Even if it does, it just seems like a superfluous item."
Yes, you are wrong, Devon. But, I suggest you not bother with the little two ounce bike strobe.