>>>And if you don't define as what it is you will have problems.
>
>I'll only have problems if I allow it to exist.
>There are no NULLS in any column in any row in any table I've ever designed and created, period.
>If I run into them in other people's data, I mutter the unutterable and deal with them.

You have no control over what exists outside your design and NULLs are out there.