[LawnGnome]

I generally think it's fine to do this sort of thing for your own benefit and open a PR as long as you're really 100% fine with "no, I'm not interested in merging this" being the answer.

Where the problems tend to arise (in my experience, at least) is when people hack on something expecting that it will be merged, get invested in it, and then get upset when the maintainer(s) aren't interested.

Checking in before starting to work on something is important if your goal is to have it merged, not just to do the work. The problem is that a lot of people start in the first category, but then move into the second category as they get invested in their project.