These days I don't do much contract work, but I have in the past. If you have such a "liability" concern, perhaps you could compose a letter suggesting that "best practice" would be for the client to understand that optimal maintenance would be that the piano had a "preparation" appointment at which any pitch adjustment, regulation, voicing, etc. is carried out, followed by the tuning on the day of the performance. I know, few may opt for the extra expense, but you get to point out such would be optimal for the piano, pianist, audience, etc.
Last Fall our chapter had an event at a new major performance center in which the acoustical architect, the piano technician, and one of the pianists spoke and gave demonstrations. Fred Mudge, the concert tuner, made it clear that there were THREE service appointments for each performance. The brand new Steinway D doubtless benefits greatly from all the extra attention.
------------------------------
Patrick Draine RPT
Billerica MA
(978) 663-9690
------------------------------