I played a fancy catering complex a couple of months ago. The gig was for a group of lawyers, and when I told them that I would have to add $300.00 for the cost of the 'one day event' insurance policy as required by the facility, they were able to convince the venue to have me sign a waiver that he previously said was not an option. One of the lawyers told told me that he thought that the venue must have had a bad experience in the past. The American and Canadian musicians' unions offer a $1M liability policy for about $140 per year to it's members - that's pretty reasonable.
Ciao,
Jerry