So let me get something straight.
You can listen to things on a radio only if you have permission of the sender.
So does that make it illegal to listen to Radio 1?
Do some airlines not have a channel (or at least, used to) where you could listen in to RT?
I would have thought from all the posts, that if its just a receiver you have, and you are only listening on published ATC frequencies, that that is legal.
If you act on any info heard, or listen to emergency channels such as police, then you are doing something illegal.
I have been to countless airports where they have the ATC on at the flying clubs, and also at big airports everyone listens in - the crew bus drivers, the handling agents, etc. Surely they are not all illegal???
If so, surely the law should be changed!