I think there was a level 2 in the RA centre, a long time time, where I was offered a free slot, because I was an M at the time (this was before GMs, in Ontario). I declined, and wanted to pay like everyone else. They were doing it to attract Ms to show up, so the matches would be classifiers, I think, but I thought it might contribute to the elitism thing which others mentioned here, so I didn't want that... I thought it was very nice of them to offer, but I chose to decline.
I think that it would be wrong for an organization to FORBID something like this, each club/MD/etc should be free to set those types of policies, but everyone should also be aware that too much of that, for the wrong reasons, can contribute to morale issues, elitism, etc, etc... So my comments are:
a) should GMs expect to get a free ride? Hell no.
b) should clubs be forbidden to offer GMs a free ride? Hell no.
Too many different circumstances, I think, to create one carved-in-stone policy.