Peterh you are of course absolutely correct. The STAR is seldom ever actually flown. One of the most commonly heard phrases in ATC: XX cancel STAR turn left / right heading YYY. So the design of the SID/STAR is practically immaterial.
I would also be interested to know why the careful design of the PRNAV STARs has resulted in procedures which complete about three S-shapes before intercepting the final approach track, and which are about 3 times the length of the conventional STAR. It rather smacks of the bureaucracy creating something which in a year or two they can tidy up and then claim credit for reducing the mileage and hence carbon emissions and "Hey, European Commission, aren't we clever boys, and can we have some more funding please?" Just a bit like the meeting in Morocco this week: the Moroccans introduced some 'directs' to improve routings out of the Canaries. But, hey that wasn't Eurocontrol's idea so the routes get rejected by IFPS. So now it will be Eurocontrol's idea and all in Brussels will add it to their KPIs and claim credit for carbon reduction.
As for PRNAV, yes it is indicated by a P in field 10 on the flight plan form. How many controllers actually know what all those different letters mean on the flight plan form? Not many, I would suggest. They rely on the pilot saying, "PRNAV unable" and then of course they will do what they always do and vector the aircraft to the ILS.
Peterh, yes, many of us have been to these Eurocontrol meetings/workshops and yes there are some of us for whom the Emperor has no clothes. Sadly there is a core group of 'meetings men' who spend their whole time trekking around Europe attending one of these meetings after another. I could mention the man from AB who does nothing else. It is in their interest to perpetuate all these meetings or else, God forbid, they may have to stay in the office and do some work. One or two others, like you and me, drift in and out and vow never to waste our time going to another one of these farces again!