That's a big ask for a site that's essentially 'morally justified' piracy.
If you want the guaranteed authentic version you should buy it from the original journal.
How do you know the authentic sci-hub isn't doing that?
You don't, though if they were, it's very unlikely they would be doing it in bulk for every file, since someone would notice at some point, either by inspecting the file or notice that a file when downloaded to a canary system misbehaves.
Targeted attacks might be possible based on the file contents or using a side-channel to ID the downloader; meaning only specific targeted users would get the malicious files.
Either way, being able to hold Sci-Hub accountable as this source would be important.
The same reason why we encrypt traffic using TLS, even if it's "mundane" traffic like tweets.