On-topic: I did a little bit of real estate dealing with the post office some years ago. The dishes and such are post office property, not the landlords, but it seems that they really do not care and generally just "abandon in place" the dish, or if the landlord wants it down, take it down and then just toss it.
Off-topic: The postal service is in the midst of a three pronged deal to cut costs. It wants to end Saturday opperations. It wants (it need Congressional approval, currently it can only shut post offices for things like lease expiration or such) to close 3200 post offices, and it is in a massive consolidation of its sorting centers (the first three digits of your zip code indicate the central place where all the mail is taken at the end of the day and sorted, mail within the zone being sent to the appropriate po, while that going elsewhere being sent on to the appropriate sorting center). In my area seven centers are being consolidated into one, the furtherest po from the center will be over 150 miles. The po will now run a truck from every single po to the center every evening and one back every morning. But because the workers in the centers are unionized government employees and the truck drivers are contractors, they will save money.
