Quirks in the drafting of laws have that kind of effect - the "club members" loophole gave us the folk clubs, the "two in a bar" exemption gave us, for example, "Show of Hands".

By way of explanation...
Western Morning News 12 Feb 2003

One band who have graduated from the Westcountry pub circuit are Show of Hands. The Exeter-based duo who have played all over the world and twice sold out the Albert Hall, believe the Bill would deny young musicians the chance to break through.

Singer-songwriter Steve Knightley said: " The grass-roots level is crucial to young talent. When you start out you need any gig at all, and it might be the only chance you will get. The two-in-a- bar rule provided us with that chance."

" If your set works in a small pub, where you are face to face with unforgiving audiences, it will work anywhere. You can't hide, so you learn to handle a crowd and build up a rapport."

"The Irish and the Scots have a living musical culture, they play at their own weddings and parties. The English don't really have that. So we are dependent on music-loving landlords who want to offer people an alternative."