So let me get this right. Are you saying that someone flying in marginal VMC on a BS from a radar-equipped unit would ask for a PS in order to get better traffic info?
No - he would presumably request TS.
If on the other hand you're saying our marginal VFR friend will only ask for PS at non-radar units, then why is he not doing this now?
The automatic assumption would be that he is then electing to fly IFR - and I am sure that some do. It's just that the term PS is not in current vogue at civil units.
But go to Carlisle, Dundee, Cranfield, Oxford and you'll see people getting a procedural service all the time. But none of them will be VFRs looking for better traffic info, now or in future.
In the near future, that will actually be an option, though, granted, they might have to anticipate remaining in VMC if not suitably qualified otherwise.
2s