I use `#####` as a sentinel for things that must not be committed, and have a git hook that checks my commits to ensure that marker is not present in the `+` side of a commit delta.
I use git to sync work between multiple computers, and I want to be able to sync work-in-progress code that should absolutely never see the light of day, so I feel like committing and pushing it to a WIP branch is fine.
Even if you only use one computer, I think it's a good idea to push these things so that if your HDD fails you can pick back up where you left off, even if it's code that's not ready to actually merge yet.