Oh, that I agree with totally, though I suspect it would be even harder to enforce than account selling (hence why the latter is "discouraged," rather than outright banned).
Perhaps two good rules to consider for filtering out potential merit abusers for red trust are on any merit transactions greater than, say, 10, or when one person gives merit to another more than, say, 5x. The latter rule will likely become less useful as time goes on, however.
I agree with this, If one person give back only one merit to sender that's doesn't mean they trading merit.
Maybe one of members here which have many merit accidentally sent back merit, can we call it trading merit? I think no!
And need real proof if they trading merit, maybe more than some times (maybe 5 times) send each other merits at short term time will be a good proof.