Just a caution to those who would consider helping the movers by being
their third party -- Don't. If the piano is insured and gets damaged
anywhere along the way and a claim has to be made, the insurance
company or van line insurance, whatever, might not pay for it because
you "interfered." They will find any reason not to pay the claim, and
unless you can somehow document that your help was perfect and the
piano was not damaged at all by your helping out, then you are liable
for the damage, not the insurance. It won't matter _where_ the damage
occurred. If they can blame you, they will.
The good guys finish last when it comes to dealing with insurance
claims -- keep that in mind. If a third man is needed, they should
have factored that into the expected costs. That isn't your
responsibility. That's theirs. They expect you to be perfect and will
hold your feet to the fire, so why not expect them to be, too? They
are professionals, so expect professional service. You will get what
you expect -- or else.