I played in a band for 20 years, mostly weddings, private parties, corporate functions, etc. We had contracts for every gig, except night clubs, regardless of the pay scale. What contracts do for you is spell out these types of things, especially outdoor gigs. For example, we required shelter, namely a tent, or other structure, adequate AC supply, and a deposit in case the gig gets canceled. Its really not so much to help out in court, although we had a few of those, its to spell out the conditions for our employment, what was acceptable and what was not. We were a very popular local band, in high demand, so we typically had no problems. We did play an outdoor party once in April, under a tent with heaters, and it started to snow. It was blowing in the tent and we pulled the plug. No problem getting paid.