Happens surprisingly (or rather unsurprisingly) often. This article http://articles.baltimoresun.com/2002-01-06/entertainment/0201060320_1_art-gallery-college-o

Happens surprisingly (or rather unsurprisingly) often. This article http://articles.baltimoresun.com/2002-01-06/entertainment/0201060320_1_art-gallery-college-of-art-exhibition/2 http://articles.baltimoresun.com/2002-01-06/entertainment/02... has a few more examples, including Joseph Beuys, who's work had been destroyed countless times. Many cases ended up in court. A baby bathtub of him filled with what looked like trash was scrubbed by politicians who partied in the museum and then used it to cool their beer and clean their glasses. The artist was not amused.