Actually, the context in this situation wasn't particularly vague. When I worked at KBIA in the early '90s, a sign posted on the the studio door said, "This door is to be shut, closed, not open, not ajar when microphone is in use."
I understood why the sign's author was so emphatic. When you're on the air, you aren't supposed to broadcast profanity, confidential information, or inappropriate chatter.
Getting a point across sometimes necessitates synonyms.
