I did a barn dance the other night which included a large number of children. There was a lot of noise - but I mostly asked them for a minutes hush while I was explaining the dance. Fortunately this worked as most of the children and parents wanted to dance, but in another situation it might not have. After every second dance we had a few minutes break where we reminded dancers to take some liquid and we played a tune which allowed time for conversation.

I know I tend to forget that my voice is amplified and I have to resist the tempation to raise my voice.

I should be pleased to hear how other performers deal with this situation - any tips?

As to paid gigs in pubs - you tend to expect noise thus the reliance on PA. If the audience is listening you can talk a bit - introduce the band - tell a funny story - but if they are not - just play and ensure at least every third song/ tune is one they are likely to know.

A folk club is a club - there for the members of the club - so it is up to the club which sort of etiquette they wish to impose, not the performer. A performer can choose to accept or turn down a booking.