Sprint's Rules of Cellphone Ettiquette

This is pretty good stuff, thanks to Jarvis for the link.

Excerpted:

"Let your voicemail take your calls when you're in meetings, courtrooms, restaurants and other busy areas. If you must speak to the caller, excuse yourself and find a secluded area where you can talk.

Don't display anger during a public call. Conversations that are likely to be emotional should be held where they will not embarrass or intrude on others."

Is cellphone usage in a courtroom a common problem? Exactly what kind of loud, angry, criminal customer does Sprint market to?