Also ...
What about airfields with noise-abatement procedures?
What about airfields like Duxford who may have regular display practice taking place?
What about airfields that are not attended all the time?
What about airfields with restrictions on the number of movements allowed?
There are loads of GOOD reasons for PPR to be required. I've had one or two issues in the past but obtaining PPR has never been a problem and in 99% of cases I could understand why it is required..