Good question.

Did you read about that solo climber they rescued a few weeks (?) ago. He got stuck on a small ledge, activated his PLB, and waited for rescue. For some reason they started searching in the wrong place (never heard the real cause of that - I suspect they only got a Doppler location) and he watched them for hours off in the distance searching in the dark until searchers gave up and waited for daylight. He tried to wave his emergency blanket at them but they didn't see him. It wasn't until the next day that a helicopter finally saw him waving the blanket.

If he had some kind of signal light (Rescue laser light, strobe, or SOS - heck, even a decent flashlight) I'm pretty convinced that he would have been noticed/found much sooner.

Though it is a marine use, I was struck by the "I Shouldn't Be Alive" where two divers were swept out to sea and boat searchers and later helicopters couldn't see them at night (the divers didn't have a flashlight).

Unless the light was coming from an area where I KNEW someone shouldn't be (like on the side of an uninhabitted mountain) I would likely ignore a strobe, but I might be drawn to wondering why a light would be blinking in an SOS pattern. On the other hand, if out in the wilderness, any light might be of interest.

BTW, I just got one of those little Fenix P1D Cree lights. It has an SOS setting, but the way they made the light rotate through the modes (if any mode is on more than 2 secs a rotation only turns it off - I don't have to flip through all the modes - Med>High>Low>Strobe>SOS - each time) , it really won't get in my way. Princeton Tec headlamps do that same thing, though I don't think either my EOS or Aurora have SOS modes - just the strobes.