This is according to the Washington Post:
"A family en route to a birthday celebration in Las Vegas this month said they were booted from a JetBlue flight over where to store a cake they had brought on board — even after, they said, they complied with instructions to move the cake to the floor.
The airline confirmed the incident occurred May 3 aboard JetBlue Flight 611 before takeoff from New York’s John F. Kennedy International Airport. However, it is disputing the passengers’ account, saying their removal was justified because their “behavior demonstrated a risk for additional escalation in air.”
The incident was not widely reported until Saturday, after video the family took was published."