Overall I like this suggestion. It's mostly harmless and intends only to help general player morale. I'd be for it.

That said, I can see new homeowners not wanting such a mark for fear that it would make them targets for buyout propositions (since they're not established with decor or a love of their new spot yet). Still... others might wear it as a badge of pride for that long-sought plot, and who knows, richer individuals might occasionally come around to new homes with housewarming gifts.

Basically, allow an option to turn it off if desired and there's really no downside.