That's a good use and I'll have to think about trying it with someone. I've toyed with it enough to know it's only as good as someone with an appropriate receiver can hear the signal. From my home, I have to go upstairs for the closest guy (a few miles away) to send it to the aprs.fi gods.
I should mention that I was pleasantly surprised to find every single beacon transmission making it through to APRS.FI - from inside the beltway all the way out past Leesburg and into the valleys between the steeper hills right down to my destination nearly in the Shenandoah River.
I suppose it helped that I was using the truck's Yaesu rig at 50W (though with a magnetically mounted 1/4-wave roof antenna) to send that data out. Next time I drive that route, I'll try the exact same thing with its little brother HT and see if any of that comes close to working at handheld power levels. Nothing like actually getting out and trying stuff in the real world where you might need it to work some day.