@Mike Connor - "I think I'd lean towards disabling the view source command on error pages entirely, it doesn't seem like its useful, and has odd side effects like this."
Er, it would be very useful, actually, when trying to clean up problems. reddragdiva.co.uk just got hit by the latest SQL injection vulnerability in Coppermine, and I wanted to "view source" to see just what the malware StopBadware was seeing was. I couldn't in Minefield. I had to do it in Konqueror. Making people switch browsers wasn't considered a good move in bug 422410 (option to view a malware page) - it's not clear why it would be a good move here.