Thanks, Shonky.
I figured it would probably nuke all RDS messages (for now). I'll fix the menu ordering for v338, and rename it to "Tuner RDS Disable", since that's what it seems to be doing.
Ideally, I'd like to be able to differentiate between the AF messages and everything else, to allow finer-grained control. But I suspect the RDS messages themselves travel over a different connection than the Tuner serial port.. Right now it's just blocking the "retune to frequency B" message, that is used by the player s/w to do RDS scanning. No retune == no scanning.
Cheers