Honestly, I think that the author already found (and rejected the solution):

I could ask for more Python developers to run with warnings enabled, but solutions in the form of “if only we could all just” are a folly.

I get where he's coming from. But the facts are: the language provides a tool to warn users, the library is using that tool, and users are choosing to turn that tool off. That's fine, but then they don't get to complain when stuff breaks without warning. It is the user's responsibility at that point, not the library maintainers'.