What happens when you've just placed toothpaste on your toothbrush, you get distracted by something in another room, and it falls off into the sink.
I had just put the paste on my brush when my roommate grabbed my attention, and right before he finished speaking, I heard a splat. The toothpaste I had just put on my brush had decided it didn't want to go in my mouth, so it committed Toothpaste Mutiny.
When a group of co-workers decide on a destination for lunch, only to find that a few select members of the group have decided to go elsewhere. These individuals inform the original organizer typically as the excursion begins, i.e. on the way out the door or while in the car.
Laurie about threw a punch when she found out that her trip to dine at the elegant Thai restaurant was the subject of a lunch mutiny to Five Guys Burgers by Tyler and Brad.