Band I used to roadie for carried a piano; not a keyboard, a spinet (well, actually, I did the carrying). Keeping it tuned & working was worth it (esp. given the options in '80-'81), but ongoing.
We did a weekend in our home club with a band whose name, if I were to give it, many would know. Their pianist came in, said Oh, good, I can use your piano! Our guy said OK.
Cat went wild, playing with his butt, his fists, his feet:
I told him You do that tomorrow & I'll come pull the damn piano right out from under you! He was pissed, but stayed within bounds the second night. Never again would I allow instrument borrowing on my watch. As Steve said, you never know what they'll do. Well handled, JV.
Peter