>Hmm, there are some thorny ethical questions here

Why would this be an ethical issue?  Whoever owns the rights authorized this so it's completely legit; even if the original is altered or not preserved that's more a historical question.  Even the European concept of moral rights is despite the name a legal issue not ethical.

Also, if the discussion was about the Criterion Hitchcock films then the soundtrack was not rerecorded:  These have the original soundtrack which has been digitally restored/remastered.  An example of partial soundtrack re-recording would be the restoration (or maybe "restoration") of "Vertigo" which had newly recorded sound effects.

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