This is a perceptive reading. But, I'd bet that if the sellers brought this up, the scammers would just say "that's something the timeshare companies tell you,

This is a perceptive reading. But, I'd bet that if the sellers brought this up, the scammers would just say "that's something the timeshare companies tell you, those scammers. In fact it's completely legal, always has been—they just want you to think it isn't, so you keep paying them. Heh, imagine it being illegal to sell your own property, can you believe some people actually fall for that?" People don't know the law, and are desperate to believe whatever willl get out from under a boondoggle that is sapping them of their fixed income. It's more likely they fell for something than that they are trying to break the law.