Daft.
I remember, many years ago when I was curator of the Yorkshire Sculpture Park, the Director decided it was time to set out one of our Richard Long Slate circles. The slates were kept stacked under a tarpaulin in our storage area. When we had set out all the slates we had, the circle was a good metre short of what it should be. Further investigation revealed that the Bretton Hall caretaker had discovered them, decided that they must be ordinary slates, not art slates, and had used some to pave his new barbecue area.
I told Pete Murray and he absolutely crapped himself - to the extent that he asked me to phone Long myself. I did, and when I explained what had happened Richard roared with laughter, gave us the phone number of the quarry and told us to order another ton, so we'd have a bit spare in case the caretaker wanted to extend the paving.
That's how a decent artist deals with that sort of event.