Hmm there are actually protocols, you know. The reason why
they're such highly paid vocations is because of the skill level of
the job itself. It has high requirements and these requirements
have to keep in line with being in the interest of the client.
No doubt that there is no 100% guarantee to a successful case
won or a life saved, but these people have to act within the
required industry standards to make sure they reach 100% or near
it. An example would be a doctor who has to follow strict surgery
protocols when operating on a patient. Should he be found
neglectful of certain protocols that lead to the eventual failure
of the operation (e.g. making high-risk choices that can
detrimentally affect the patient's life without getting consent)
and thus lead to the subsequent death of the patient, he can be
sued for negligence. But if he tried his best within the industry's
safety requirements and the patient still died due to causes that
are uncontrollable/unprecedented, he should not be held
accountable. In any case, it is common sense and common knowledge
that such procedures have success and failure rates. It is also the
responsibility of the doctor to brief the patient of said
success/failure rates so that the patient can have a realistic
understanding of the situation.
In any case, going by your logic, employers would also be at
risk of not having 100% effort from employees they hire. Humans are
not goods to be sold or traded, and their services are given with
remuneration for the effort, time and money obtaining the necessary
skills for them to assist the organization.
So yes, I think it is very fair.
Don't you think it would be very naive to expect 100% success
when it comes to services given by human workers?