They should have added a note to the end to clarify conditions and say that if this does not apply to you, then feel free to ignore it. Looks like they have lots of false positives but they didn't account for that in their letter.
I think they should've just sent a letter to all owners (reworking their language, of course).
With new locations popping up all the time, this will become an issue for many more owners as time goes on (a supercharger just came on 4 miles from my house and job). It would be best if they just let everyone know of their position on superchargers. Some will ignore, some will respect the intention, but at least the whole fleet will receive the message.