Although overload is a real thing, after testing LITERALLY every GMRS handheld manufactured in the last 5 years, I have never, EVER, NOT ONCE seen any overload/desense issues unless the radios were closer than about 75 feet, an 90% of the time they had to be closer than 25 feet or so.
To claim that overload is an issue at up to a 1/2-mile, on its surface, seems like a preposterous over-exagguration, based on my very extensive testing. But that's just my experience..