This isn't so much as a question, as an idea which I think would be helpful. I decided to post it here to get feedback on the idea. I'm not sure if this isn't exactly the right place to post it, but I wanted to see what you guys think.
My idea is to create an code checkin policy which displays a diff of each modified file. To be able to check it in, another programmer has to 'sign off' on it; this is done via the other programmer using either Active Directory authentication, or just putting in a username and password from a random database. Obviously, a user wouldn't be able to sign off on his own code.
Ideally, it could be mixed with the sample from Microsoft which applies a checkin policy only to specific files, or to ignore small changes, and so on.
Or, is there already such a third-party policy?