There is a HUGE difference between driving in one's car on public highways and climbing a snow covered mountain in early winter.
Nonetheless, I always carry a cell phone, a CB radio, chains for all four wheels, flares, flashlights, tow strap, etc in my 4WD pickup year around. I have helped several people out of ditches and up steep hills.
If I were a hunter (I'm not) and drove the mountain backroads of Oregon (I don't) in the fall and winter, I'd be sure to have a GPS unit and I wouldn't travel alone.
I just don't understand the mindset of someone who takes the kind of risk involved in summiting Mt. Hood in the winter and doesn't take an MLU with them. Cell phones have been proven to be of intermittent value and after several days, no good at all due to battery life.
Is there a logical reason to not take an MLU on a climb or is it just machismo?