Honest to God question here. I have multiple characters on one server (on many servers actually, but lets just stick to my main server for this). My multiple characters are spread across 3 FCs, all of which now have their own house. Which two FCs should lose their house since I'm a member, or should people like me who are members of multiple FCs be forced to pick just 1 FC to be part of? Limiting to only 1 FC house per account per server is fine for not being able to purchase anymore, however, if you're wanting to enforce the rule completely, not just the purchasing aspect, you're opening up a whole new can of worms that I'm pretty sure you haven't considered.
A few years ago, there was a glitch where people could add their alts to their friends list. Those people can send themselves mail and add themselves as tenants at their homes. It was not something ever intended as part of the design of the game, and it definitely is something new players cannot do. Should SE go back and remove this from the old players? Should anything and everything that has ever been grandfathered in be removed and "fixed"? I know I'd be pissed if my lofts that I was able to place because of a UI glitch that was fixed with 4.2 were taken from me and I had to try the new (much, much harder) way to hope to get them back.
I really don't understand why you are filled with so much hatred towards anything being grandfathered in. I read a great example in the forums somewhere (I may try to find it later to add the quote), but it basically said in real life if you build a house, you have to build it to the codes and laws as they are right then. If your city/ town/ county/ state/ country/ whoever changes the codes which housing has to be built to, you don't have to rebuild/ fix your house to meet those new codes even though any new houses have to meet those codes. If you try to upgrade your old home, then you have to meet the new codes, but just because the laws (rules) changed, doesn't mean that they should be retro-active and everyone in the town should have to rebuild everything just to meet the new coding. That's how things get grandfathered in, and it's almost always a better system for everyone.