To be fair, the Springer empty PDF paper for $39.95, has zero errors, and zero plagiarism, so it is above the bar of their other paywalled proceedings papers.
That page says that eight years after the supposed lawsuit "Batt admitted that the alleged legal dispute had been a publicity stunt and that he had actually only made a donation of £1,000 to the John Cage Foundation."[1] I guess that he plagiarized it is sure even if the copyright claim was not litigated.
https://en.wikipedia.org/wiki/4%E2%80%B233%E2%80%B3#Plagiari...