what if others will only buy/ sell merit even though their post is garbage? they should be ban
If the seller is a merit source, they should be stripped from being a merit source and theymos should reverse merit transactions at his discretion. If it is a regular user selling merit, theymos might reverse any merit transactions at his discretion. (Not quite sure if he will or not.) Furthermore, theymos has made it clear that dt giving red trust to merit sellers is acceptable.
As I've said before, I'm not really worried about it. Especially at those high prices (plus the risk of being red-tagged), it's enough of a barrier that it should still serve its intended function of creating a significant cos[t/barrier for garbage-posters.
BTW, if any merit source goes rogue and sells a ton of merit, then I will probably go through the transaction graph and undo all of the transactions touched by that sold source-merit. Merit ain't no immutable cryptocurrency!
If a DT member tags you for something stupid involving merit (ie. probably anything less than selling merit), then they're not going to be a DT member for much longer.