git-submodule/before-rebase hook

I just discovered git-submodule today, and already I can see it making my life a lot easier. I develop several modules that are used in two different projects, and being able to check in changes from the submodule in either project is something I have been wanting to do for a while. But there is one shortcoming in git-submodule that I haven't figured out how to overcome... yet.

When I make a change to a submodule and push that change to the parent repository, the change appears to all other users of the repository as a modification to the submodule commit version. A few people at our company use 'git ci -a' to add all of their changes, and I'm afraid they are going to unknowingly revert the submodule back to a previous version. So my plan was to add a post-pull hook that does 'git submodule update --init', so that people who don't do development on the submodule will get updates every time they pull. Unfortunately though, there is no such hook in git. I thought post-merge was going to work, but most people at our company use 'git pull --rebase', and post-merge isn't called in that case. The post-checkout hook is called, but the pull hasn't been completed at that point, so updating the submodule doesn't work. Alas, if only there was a post-rebase hook.

Any ideas other than patching every employee's git source to add a post-rebase hook?

Thanks, Justin