What exactly should SE do? If they fulfill the requirements for purchasing, then they are allowed to purchase. How exactly is SE going to prove wrongdoing here? It's not against the rules to buy an FC house on a lower level character. It's also not against the rules to be the only one in your FC. It doesn't necessarily mean house flipping, either. I have friends who do not want to join another FC and have made their own FC because they were going mad from spam invites. I had another where everyone abandoned him and the house passed to his hands when he was the newest member. SE is not going to be able to filter out these legitimate FCs from those who may be attempting to circumvent rules. Not unless they implement further restrictions like the current "Can't buy if in an FC with house" rule that really does nothing except punish legitimate players.