I've seen auto-formatters make things considerably worse in terms of readability just to make them fit into a particular style. I think that real people will always do a better job at making things readable and adhere to the particular style. I generally agree with Robin's point that now is a good time to go in and clean up by the code due to the low number of outstanding patches prior to a release, but anything entirely automatic gets a -1 from me. Also, for areas where known patches are outstanding, it probably makes sense for the owner/patch author to do the work, at least make the patch conform to the style.
I agree that going forward committers should be validating the style of checkins and bouncing patches back to the contributor if they don't conform to the style. If something is important enough to contribute, it is important enough to style it correctly. I suspect the majority of these errors are made out of ignorance as opposed to sloth. That said, it should be nearly effortless (and have a zero time cost) for the committers to validate style using which ever tool they use.
