I haven't had any significant RF-related trouble.
You have been lucky and as it becomes more and more difficult to deal with traditional wireless in the TV bands some day your luck will run out.
The truth was in Henry C's signature ... that every radio in the world is interfering to some extent with every other radio that is turned on. Every RF signal there is is coming down into your receiver's antennas and you are asking your receiver to deal with it. So "best practices" is to do everything you can to minimize potential problems and lighten the load so to speak. Once you add up enough little problems your radio fails.
I'm guessing that in Matt's case he is getting enough separation by using his IEM paddles located a bit away from the mic receivers.
So with all the new competitive devices that are expected to be turning on in the next few months and years we'll see how your luck holds
