Account selling undermines our Merit system as well because Account selling is similar to buying Merit. Buying Merit is not allowed, too.
Merit sources aren't allowed to sell Merit. Other than that, it's allowed to buy Merit, and that's probably because of the same reason why account sales are allowed: it can't be stopped anyway.
Gosh! LoyceV you scared me by this post. That except the merit sources, any other person can buy or sale merits. I haven't read something of this nature in this forum. Merit trading had always been known as a serious offence even more than account selling.
Allow me to quote theymos on Merit sales:
Merit sales, transfers to aliases, back-and-forth trading, etc. are not much of an issue. All illegitimate merit will decay, and will account for a tiny and very expensive fraction of the total merit economy. It's basically a rounding error; fight it where convenient, but waste no sleep over it.
Oh! No No... this is true. This simply means there are no
firm rules in BTT.
That's why there is more or less consensus over it: if some buy or sell merits, it means they trade a measure of recognition on the forum and it makes them dubious counterparties. So trading with them has higher risks, so they deserve red marks in a trust system.
So right, it is not a matter of rules, but it is a matter of reputation system of the forum.