What happened to the people that scammed in the past in house transfers?
Depends on the scam. Those that sold houses in guardzones inthe past sold 'grandfathered' houses. So the people that bought them didn't suffer as much as in this case. The point isn't that the scammer should be helped in any way, but like the bans on people that owned 'duped' items vs banning those that sold them, it seems like EA is focused on punishing the victims.
The person that places a house in this case is in a win win situation. They either sold the house for a big profit or they can drop the house and recoup their costs. Either way, they aren't out anything. However, those unlucky ones that were tricked into buying said houses are going to suffer. Once again, the innocent players suffer because of EA's poor design and the griefers gain. You sorta get the feeling that this is how EA wants it. I can't imagine so many examples of this practice not being intentional.