Unauthorized use of mail relays is already preventable. Why legislate against something (which merely establishes a penalty for it) when you can stop it from happening, cold. Just install qmail -- by default it prevents relaying. http://www.qmail.org.
[ For the sake of truth, I run that site, and I also provide commercial support for qmail -- but I do both of those because qmail helps stop spam. ]
So does sendmail. But it doesn't have cute mailer-daemons and "hope things work out!" messages like qmail. -- jamie g.k. rishaw dal/efnet:gavroche Internet Access Group New Network Operations #: 216.902.5460 __ Network Operations/TSD DID:216.902.5455 FAX:216.623.3566 \/ 800.637.4IAGx5455 DES: Help Crack the code! http://www.frii.com/~rcv/deschall.htm