how do PP make money
perhaps there is a charge back towards the airline that is "using" their facility.
There are several levels of PP membership, the lowest being a turn up and pay, to full unlimited access.
The fact that Srvisair or other has no loungein T5 is perhaps that it is a BA terminal.
I have been a member for many years, and it made EasiJet almost a human carrier.
As to getting in with out a boarding pass, never tried it.
glf