I do check the LICENSE and CONTRIBUTING files before I contribute. It is likely that I would have not contributed to such a project in the first place. It doesn't change my point, namely that a project where I cannot contribute fixes for bugs I encounter is one that I have no desire to use.
BTW, the reason I mention sending PRs for bugs I encounter is that, when I do encounter a bug I don't immediately file a GH issue and make it the maintainers' problem. Instead I act upon it just like the maintainer would, by checking the source to figure out why the bug is happening, `git blame` etc to see what commit added that code, whether the issue I'm encountering was already identified or discussed when that code was committed, and so on. So as a result of doing these things I often end up either knowing my issue is by design and that I was doing something wrong, or end up having enough knowledge to be able to construct a bugfix myself.
BTW, the reason I mention sending PRs for bugs I encounter is that, when I do encounter a bug I don't immediately file a GH issue and make it the maintainers' problem. Instead I act upon it just like the maintainer would, by checking the source to figure out why the bug is happening, `git blame` etc to see what commit added that code, whether the issue I'm encountering was already identified or discussed when that code was committed, and so on. So as a result of doing these things I often end up either knowing my issue is by design and that I was doing something wrong, or end up having enough knowledge to be able to construct a bugfix myself.