I obviously haven't really explained what I meant.
All of the above is fine and sensible. But there are the airfields which say that all they meant was that you should call up on the radio. And the ones which when you do visit say: "Well, I know it says PPR, but we don't really care. Come in whenever you like".
The point I was attempting to make is that PPR has acquired so many different meanings that it's very confusing. I can see some people don't think so, and that's fine. But don't you think it would make more sense if they said "PPR by phone", "PPR by radio", or whatever they actually mean, or leave it off if they don't want it.
I phone up anyway, if at all possible, to make sure everything's OK. I think it's a good idea. But that's not actually the point.