> For this specific issue, the ResourceWarning is correct. I don't
understand the use case of explicitly turning this warning off on this
specific example?

No, on this specific example the child processes do terminate properly as the parent process terminate. There is no extra resource consumption so the warning is incorrect and annoying.

> If your output is flooded by ResourceWarning warnings, it's easy to
configure Python to ignore them. Example, simplest option: python3
-Wignore script.py. But you are only going to hide a real issue in
your code. ResourceWarning exists to help you to reduce your resource
consumption.

At the moment the outputs are flooded with "exception ignored" messages that show how well this was thought out. Asking users to add -Wignore options for perfectly legitimate applications also shows how much consideration is being given to user experience, but we should not be surprised because that is how Python3 is being developed?

Please remove this mess until a proper design is made and documented (3.7).