I've never seen any performer bring his own enforcers and force the audience to listen.

I have - just the once. It was at the BBC Folk Club - "Clanfolk" - in the Marquis of Clanricarde in Bayswater in the early 1970s. The booked act was Martin Carthy, and I was the then organiser and booker. Just as Martin had started his act, in walks Dominic Behan, pissed, with two large Irish blokes with him - very obviously his "minders".

Behan stalked to the front of the stage, pushed Martin in the chest - Martin stumbled back, luckily into a chair - and then proceeded to sing Irish rebel/anti-English songs at the top of his voice. Being in no mood to tackle two large blokes - though I would have happily slung Behan out if he'd been on his own - I went downstairs and summoned Danny, the even larger Irish landlord. Up came Danny and out went the trio.

What struck me afterwards was Martin's calmness and patience at the time - though he remembered it all with a grimace when I met him, many years later at a Christmas concert in Shoreham!

But that's the one and only time I've encountered such an incident at a folk club.