In which of the following cases is a conviction of the named defendant for robbery LEAST likely to be upheld?
Johnson forced his way into a woman's home, bound her, and compelled her to tell him that her jewelry was in an adjoining room. Johnson went to the room, took the jewelry, and fled.  A confederate of Brown pushed a man in order to cause him to lose his balance and drop his briefcase. Brown picked up the briefcase and ran off with it. Having induced a woman to enter his hotel room, Ritter forced her to telephone her maid to tell the maid to bring certain jewelry to the hotel. Ritter locked the woman in the bathroom while he accepted the jewelry from the maid when she arrived.  Hayes unbuttoned the vest of a man too drunk to notice and removed his wallet. A minute later, the victim missed his wallet and accused Hayes of taking it. Hayes pretended to be insulted, slapped the victim, and went off with the wallet.