In any amateur pastime you are bound to have people of varying ability, if you have had one bad evening you should have ay least another attempt, have a word with Gil in the Plough, John in the Endeavour, Sue in the Black Horse or Chuck in the First In and you may find that the folkies tend to be good drinkers who don't cause any bother, I.E Good Customers, if your buisness can do without the added trade then fine, if you're looking for extra trade you could do worse than buy yourself soome earplugs !
Tell you what let me know which pub you run and I'll see if we can't liven it up some night with some stonking singers and musicians, making sure dirges are discouraged !!

Cheers

Raggy