Interesting that this has cropped up.

I used to sign my copies then send them out....until this happened to a local operator:

He took a booking, sent out the paperwork with his signature on first. They phoned up and cancelled. After the party, he got a nice letter stating that he had failed to turn up at their party, and had subsequently ruined the whole thing...so they were seeking legal advice. They produced one fully signed copy of the contract as proof of booking!

He was ready to fight it in court if necessary...but the "client" bottled it in the end and admitted they had gone cheaper, who was a no-show, and because they had the original contract lying around...thought they could make a few quid off of it.

Had they not bottled it and gone through with it then god knows what would have happened. On the face of it, he was a no show to their contracted gig...