Pretty sure buying houses for the sole purpose of throwing them out back to resell for a profit is against the tos. All people need to do is be proactive about it. Don't give in to abuse by these people. After the houses are implemented and you see a bunch of pfs up offering to sell plots, report them. That's what it's for. Take pics of their pfs for prof and time stamp the moment you see this happening.

By enabling this behavior, they will keep eating away at the plots if no one stands up. But by means is this no witch hunt. Don't spread gossip about so and so committing these acts. Let the gms do their job after you report and move on.