"Magic" null argument testing

Warning: here be dragons. I don't think this is the right way to check for null arguments, but it was an intriguing idea.

Jon Skeet spends way too much time trying to figure out a better way to null check than the first solution he has (which is the best).

How about this: nothing can ever be null unless explicitly allowed. I've mentioned it before from another post I found. I really like it more and more.