Neither shalt thou use body language in general:

A raised eyebrow, loud guffaw, smirk or other facial expressions could all be banned in future political debate under rules proposed for the city council of the Californian city of Palo Alto. In a bid to improve civility in the town's public discourse, a committee on the city council has spent hours debating guidelines for its own behavior.
"Do not use body language or other nonverbal methods of expression disagreement or disgust," a new list of proposed conduct rules reads.
Another rule calls for council members to address each other with formal titles followed by last names, formality not always practiced in laid-back California.
"I don't want to muzzle my colleagues," councilwoman Judy Kleinberg, who headed the committee that drafted the rules, told the San Jose Mercury News. But "I don't think the people sitting around the cabinet with the president roll their eyes."

Quite how Ms Kleinberg and her committee intend to prevent people from using body language, short of taking people's bodies away from them, is not explained.