Fluffy 5 interesting question
Good question deserves an answer. Peer comment will only tell if the answer passes muster!
There have been a few incidents where promising (and indebted) CPL students have been injured (or worse) - either due in part or whole to the handling pilot and/or mechanical problems.
The Examiner and the owner/operator of the heli will have the benefit and protection of aviation liability insurance, usually a minimum of £1-2m depending on type an operation (often £5-10m on turbine).
The injured CPL student (or his next of kin) will have a valid claim if the facts prove fault of Examiner and/or machine.
The aviation insurers have a commercially vested interest in minimising claims, hence maximising air safety as well as coaching operations not to admit responsibility in any accident. Some aviation insurers are also known to look for reasons to withdraw the insurance policy to cover a given claim - and they will use all available small print.
The UK Heli world has a new aviation insurer this year, and I expect premiums might actually decrease a tiny bit in the short term.... a nice thought.