In my opinion this will pretty quickly solve itself though. Accidentally committing keys to the repo potentially ruins your entire week. With a default disallow all list, you might have one bad deploy oopsie and then commit the files.

One problem I see all the time is that people are not using proper tools.

Yeah command line is cool and all but I do believe most of the developers should be using UI tooling where staging area is showing nice diffs.

Built in GIT handling in IDE usually is better than command line but also usually worse than dedicated tool like GitExtensions or SourceTree which are free and are super convenient for staging.

People don't know they don't have to stage whole files but they can stage hunks, well in command line it is too much hassle for me but in GUI tools it is no brainer.

I recommend looking here: https://git-scm.com/tools/guis

(it might be that you will be waaay cooler using GUI tool because you will be able to fix things others can't ... saying from my experience)