The same’s probably true of a police box, especially if two or three people walk in in quick succession or one person goes in and stays for a long while.
I like the utility tent idea, especially if you pair it with an “Employees Only” sign. There’s been one outside my local grocery store lately too. Hmmm…
It lost its abilities after making a landing in a junk yard. The show started in 1964, but no mention was made of how long it had been there by then. So if blue police boxes were being removed from service, well, that one looked like it had been.