There are quite a number of people who like tinkering with birth years for the hell of it. it's one of the most common forms of vandalism. A good deal of the present BLP problem is the difficulty of preventing this on the more obscure articles. It would be counterproductive to have a policy to accept unsourced corrections of things like that, uncontroversial though they may seem.
David Goodman, Ph.D, M.L.S. http://en.wikipedia.org/wiki/User_talk:DGG
If someone says that a relatively uncontroversial fact in an article about themselves is wrong, we should fix it. If our process says we shouldn't listen to them, then we need to fix both the process and the article.
If you really doubt that the person themselves is sending you a correction, then fine. But that's only good if you really have some reason to doubt it's them. Saying "what if it isn't them" and then stretching it to cover all situations whether you believe it's them or not is just elevating process above people.