This is an excellent point.
I know that the cops do check to see if you aren't being held against your will. A friend of mine once hit her speed dial button for 911. It was an accident, and don't ask me why she had 911 on speed dial. Anyhow, the cops showed up right away and, even though she told them it was an accident, they searched the entire apartment including the bathroom and bedroom to make sure that there wasn't really a perp in there forcing her to send the cops away.
Really good point, Jfor.