Chief Wiggum, it's really simple: If they don't have to use their radios, then Avcharges (or whoever they're called) can't record the callsign of aircraft landing at the various regional airports and therefore can't collect the landing fees which rightfully are due to the aerodrome operator.
A significant cost saving to the non-radio user and a loss of fees which pay for the upkeep of said aerodrome.
I guess we could use an "honesty box" system where users could place a few bucks in the kitty when they land.
But we all know what a bunch of tightarses they really are, and that this would never work.
