Hyperbolic reply. You take reasonable steps to prevent it such as deleting threads with the same effort that is used to delete what is considered spam or off-topic. Then you warn people that accounts can be sold if it is a problem, you don't publically support account selling. That make this site (and Bitcoin) look ridiculous and irresponsible and possibly even create a legal liability. That is why you don't see this at most other forums.
The reason you dont see account selling at other forums, is because their demographic is different. This isn't the hello kitty fansite forum. We cater to the bitcoin community, all of which knows basic anonymity measures and know how to bypass any measures that we could possibly put in place. Why create laws if we can't enforce them, it just makes us look like jackasses.
SaltySpitoon, its a good post but we all know that politics relating to the trust system is what runs this community now. You can very easily bring to light the actions of a user not in the default trust, but the posters in the default trust have a pseudo immunity to scam accusations, to where they can do whatever they want and get away with it, because any negative trust they receive won't show up on their profile, and they can easily enlist fellow members in the default trust and use them to discredit their accusors through posting fraudulent trust ratings. its a pretty broken system in this aspect. It is my belief that only moderators and admins should be allowed into the default trust.
How people regard others on the default trust list is up to psychology. I can't tell people how to use the forum's trust system. Thats really a social issue. I've seen plenty of people on the default trust list get called out for being a scammer, and they were given no special treatment by the community. Pirate@40 was around before the trust system, and the amount of people cheering for him rather than pointing out their suspicions was completely disproportionate, even after he started to slip. Most of the people on the default trust list have in the past done something for the community, whether that be to providing a "trusted" service or product, its understandable that no one wants the good guys to become scammers, but sometimes it happens. I really don't think there is a huge issue with the forum's trust system. If you have an idea on how to fix it, we are all ears.
That being said, I'm not a trust system shill, I've never been a huge fan of it, but I understand its uses. If you want someone off of the trust system, you have to prove it to the people that added them. I've seen plenty of people removed. Actually how the system works is pretty interesting. If I add someone to the default trust list under me, its a blow to my reputation if they do something, giving me incentive to only add those that I truly trust. And if someone that I trust messes up, I will want to know immediately so I can remove them and stop the damage to my own reputation.