DaveInDenver
Rising Sun Ham Guru
You'd have to check FCC licenses but GMRS many years ago was legal to use for businesses and if they kept their license up-to-date they would be grandfathered in.Funny you mention that, Dave. There's at least one hotel in Moab who uses GMRS for their staff. We'd hear them anytime we were near the top of a ridge.
Mark
If memory serves the GMRS rules for business use changed in 1987. So at this point it's extremely few licenses that meet this clause. And it's restrictive in that you are not allowed to make any major modifications (this being moving repeater locations, that sort of thing).
The honest truth is it's impossible to know without physically checking their radios. But if you're hearing them many miles away there's the possibility of high power (5 watt) radios or a repeater, which would be GMRS.