As a 40-year veteran of the Irish/Scottish/Celtic/Folk scene here in the U.S.A., I tend to agree with DebC.

I've performed (headlined) at legendary folk clubs such as Passim, Godfrey Daniels, Caffe Lena, as well as at festivals as diverse as Hardly Strictly Bluegrass, Milwaukee Irish Fest, Longs Peak Highland Games, Celtic Classic in Bethlehem, PA.

If a club organizer doesn't want to hire me, I don't take it personally. If he thinks I won't suit his club, so be it.
But the strangest reason I ever got for not being booked was from a lady who ran a folk club in Connecticut.
She did not like the color of my guitar.....