I picked a couple of paper books off my shelves to have a look at that warning. I tried to pick wildly different books, and always chose a different publisher. Most of them had a warning. Of the handful I checked, Pocket Books Fiction, Gollancz, and Pan Macmillan Australia notably don't carry a warning about disfiguring the cover prior to sale/trade. Here's the list:
Cabal by Clive Barker (Pocket Books Fiction, 1995 ed.) - no warning.
The Forever War by Joe Haldeman (Gollancz, 2009 ed.) - no warning.
Gallipoli Sniper by John Hamilton (Pan Macmillan Australia, 2008 ed.) - no warning.
The Songs of Distant Earth by Arthur C. Clarke (Grafton, 1987 ed.) - warning.
The Bell Jar by Sylvia Plath (Faber and Faber, 2013 ed.) - warning.
The Nickel Boys by Colson Whitehead (Fleet, 2019 ed.) - warning.
... Slow day at the office today.
