There are different levels of legal cover here. The venue want to make themselves not liable for loss or damage to your equipment. You want to cover yourself if someone trips over your tripod and gets injured or spills a drink over your camera bag.
In the UK if you want to protect yourself from being sued for any accident that you may cause you would need public liability insurance. It used to be that venues had this as part of the drink licensing laws but now it is down to the individuals using the venue to cover themselves.
As the venue are contracting you to cover an event I would make sure your contract terms and conditions specify who is responsible for what as well as getting all the copyright releases for use of the images you take sewn up.
Nikkor AF-S DX; 18-105 f/3.5-5.6G VR, 55-300 f/4.5-5.6G VR, 35mm f/1.8G
Speedlight SB-700 http://keystrokesukimages.com