well andy 7, in my local village in ireland i could do just that if i wanted , which illusrates the difference culturally between ireland and england,neither would it be considered middle class.
this is because there is still a respect for trad music
   in fact last year myself and jim bainbridge did turn up in a rural pub in kent [we both knew the land lady[ but had not made any prior arrangement and we sat down and had a great session of songs and tunes, and that was in the uk.
it is more a question of picking the right place [ that means prior knowledge] layout [ preferably two bars and not shooshing people]., and how you do it.
however in PFRS CASE THE FAULT LAY WITH THE PUB OWNER OR MANAGER, in not clarifying what he wanted in the pub