I was lazy when I push all to my remotes, since I sometimes switch naming conventions/don't include all my remotes for EVERY repo.
Also, I am too lazy to make a remote that includes ALL my remotes in one (http://stackoverflow.com/questions/5785549/able-to-push-to-all-git-remotes-with-the-one-command).
Hence, I have the scripts that parse out and then for each runs git push <found remote> master. It defaults to master, but if you want you could easily change the push command to be "git push <remote> --all". I just am lazy and push EVERYTHING to master.