`git commit` with the `--author` option

Thank you for git! I use it hourly. It is orders of magnitude better than vcs, cvs, subversion, clearquest, sourcesafe, and a number of others I have used, but can't remember right now.

I was excited to see the `--author` option on the `git commit` command, thinking that I could use it to set arbitrary authors for git commits. Reading the docs, I expected to use it to, "Specify an explicit author using the standard A U Thor _author@example.com_ format."

It seems from stackoverflow and this list that git won't do that unless you have an author specified in your config somewhere (`git config user.email` and `git config user.name`)? Links to sources available on request (your system rejected my first email).

Does the email you set in the `--author` option have to match the one in your config, or can you set it to anything once you have a random user.email in your config? Is this option just for choosing between pre-configured emails?

I think this option would be much more useful if it worked without also setting your git config.