The issue with making houses locked to FCs is that many players won't get a chance to decorate it the way they want it. The apartment is a sad empty square, and so are FC rooms.
If you give all FC members permission to place and remove furniture, you risk players stealing stuff for whatever reason, including selling it via PF. GMs won't help out with these reports, so you're better off limiting access to that for everyone except the FC master.

If the above person thinks FC lacks real content (I kinda disagree since I do like the Company Workshop), then there's no real reason to lock it to FCs.

What I do think should be done is check for a minimum number of FC members. My previous FC plot was purchased by a FC of a single member, had it locked, had no furniture placed outside, and I'm sure it was basically a warehouse. It was relinquished during the Shirogane fiasco, so I'm guessing they're now ocupying a space somewhere else.