Wise words.
There is very little loyalty in the Entertainment business ( ask a few ripped off 60s rock stars
)
The indemnity is way out of order and you HAVE NO LEGAL NEED TO SIGN IT because you have the usual suspects--( hopefully )
PLI
PAT
RISK ASSESSMENT
PRO DUB
Employers Liability insurance if you "employ" other DJs under a Contract of Service --you may need to check that.
You can either tell them you have all necessary Insurances, Licences and Risk Assessments to comply with the law of this Land and your not signing it because you have nothing to fear OR run the risk of being booted out.
Incidentally the PLI Insurers would probably have a HEART ATTACK if they knew you are accepting Liability in advance and you may invalidate your own Policy by doing so.
Remember that old saying --if you have an accident never admit Liability --thats why--because the Insurers NEVER admit liability unless its an extreme case--they just make compensation payments WITHOUT ADMISSION OF LIABILITY.
I guess you could use that as a reason--
Even if under the Unfair Contract Terms Act you could claim it was unfair to impose this condition on you--you are left between a rock and a hard place trying to prove it--should I change that to your highly expensive Lawyer might have that problem as you dont know anything about that apparently .