Before anything, I have to say that I do not advocate uncritical use of this solution. A good system should validate all input and keep its entities valid at all times. If you end up needing this one, you shold be needing it because you're creating...
I thought of this the other day and wrote a post about it, but my browser crashed when I hit "publish". Might have been a cosmic hint to think it through, but here goes again. :P To fix a long demanded requirement of uploading multiple files...