Python-modernize and absolute_imports

In the Plone documentation at
you are advised to exclude python-modernizers fix_import fixer.

But why?

Python 3 won't find implicit relative imports any more, so you have to rewrite them to absolute imports anyway (or explicit relative imports).

If I do not import absolute_import how would I find the imports which needs to be rewritten while I am still on Python 2?

I certainly can manually view every single module (in my case 455), but that doesn't sound like a good plan.

Of course, once you are on Python 3, you certainly notice at once which imports do not work any more.

Thanks for any input!