In ,
dpb typed:
Twayne wrote:
...

By law, there has to be. It's a legal requirement, I'm
afraid. ...

Cite? It certainly isn't federal law (or hasn't made
itself known locally anyway) and see above for local
situation here...

The above says nothing. I'll give you a hint for citations: Start by looking
at ANSI and perhaps a trip to your local town hall.