Who knew so many little people would throw such a huge party?

Under the Rainbow (1981)

In World War II era Los Angeles, the manager of the Culver Hotel leaves his nephew in charge for a weekend. The nephew changes the name to the Hotel Rainbow and overbooks with royalty, assassins, secret agents, Japanese tourists, and munchkins. Secret Service agent Bruce Thorpe and casting director Annie Clark find romance amidst the intrigue and confusion.