The nerve of people these days.
It's rather more common than you might think, and a great tragedy.To counterbalance it, we have quite a bit of music which was preserved by relatives despite composers' express wishes that it be destroyed.
Fantaisie-Impromptu!
Okay so today I was talking to my violinist buddy and he was like...Yeah man, my violin teacher visited Rachmaninoff's granddaughter, or great granddaughter or something, and there was a vault of like 100 unpublished rachmaninoff pieces..........She's not releasing them because she wants the copyright.
Even if this relative of Rachmaninov might have been entitled to all of any poart of the copyright in these pieces (of dubious origin), she'd not be receiving it now because, under the widely-used 70-year rule, Rachmaninov's copyright expired at the close of last year.Best,Alistair