Is this debate over flashlights only?

I ask because if you are considering this for an actual rescue strobe (as in the xenon strobe type like the ACR Firefly series), then having them emit an SOS signal is impossible as fas as I know. The xenon bulbs that those strobe lights use are much like the flashbulb in cameras (or maybe even exactly like them). The don't have separate settings for dits and dahs. They are designed to only do short, albeit blindingly bright, dits.

If you are talking about a flashlight emitting a constant flashing versus an actual SOS, then my opinion is why the hell not. Most flashlights that have a flash/SOS function are LED lights anyway. The electronics to make an SOS and a constant flash are pretty much the same as the electronics that make just a constant flash, it's just a different IC chip. That different IC chip certainly isn't too big to include in the light, and the Photon micro-lights prove it. (They have both the constant flashing [3 speeds] and the SOS function built-in and look how small they are.)

As far as the "extra" SOS mode complicating the interface, I feel that if your flashlight does more than turn on and turn off, the interface is already too complicated for 50% of the population to figure out. What's another mode gonna do? Make it so 51% don't get it? And you know what those people who don't get it are gonna do? They're simply going to turn the flashlight on, then either stick their hand in front of it or sweep the light side-to-side in intervals required to make constant flashing or SOS.