A flight that left New York City (Kennedy International Airport) had to make an emergency landing after an angry passenger allegedly started making threats. The Alaska Airlines flight was headed to Los Angeles but had to be diverted to Kansas City, where the unruly traveler was arrested. The man got mad about the line for the bathroom. He was heard saying: “You wrong. By making seven people wait here to use the bathroom, while the whole bathroom up there is empty, it’s wrong.” The coach passenger was upset when he couldn’t use the empty first-class bathrooms.
I don't know what the protocol is but it sure seems silly to create a long liine when they could have allowed some coach passengers to "go" in first class.