Insurance Suppose someone twists their ankle at a dance, or slips and breaks their arm. They then decide to sue for loss of earnings. I've not known this happen, but it could, and I can invent scenarios where the caller might easily be judged liable for not exercising due care. In that second case it might be held that the caller should have inspected the floor and at least have warned the dancers. So you may wish to be insured.
Links There are lots of dance pages on the web.
The ones below are particularly relevant to barn dancing. A very well organised site. Scottish ceilidh dances are extremely well described on Ian Brockbank's page. Contra dance notation from the Cambridge Contra Dance Club page - mostly too hard for barn dances. Eric Foxley's page on playing for dances is worth reading even for callers.