I think you're underestimating the percentage of BM players who are poor students.
I suspect it would deny access to at least 50% of the player base.
Agree, and, to pay will not avoid all cheaters. I can assure to you that in another game, we have hundreds or thousands of clones that pay to play. It will be just another kind of cheater, richest ones.
It took some time to me to understand this OOG and IG thing. There are many and lots of reasons to have a one account/one player rule and we could discuss one by one for years, and at the end of the day many will still disagree.
BM is a special game. If there are players that dont see this and cheat, and in a way that make it difficult to dennounce, let them do it. Ignore them, move out. Imagine what could had happened if everyone that was not cheating at aurvandil moved out to another realm leaving the cheater alone?
They are getting creative, be more.