In trying to force Edna and Seymour out of the school, the Springfield police attempts to flood the area with music. This is similar to a tactic that the US troops used during Operation Just Cause in an attempt to force Manuel Noriega out of the Vatican embassy in Panama City.
The trivia items below may give away important plot points.
One of multiple sieges in Springfield Elementary. Other sieges include "Bart Stops to Smell the Roosevelts" and "Skinner's Sense of Snow." "Skinner's Sense of Snow" started as a weather emergency and had no specific agenda. The other two were successful in their agendas, bith of which involved someone losing a job unfairly, then getting it back.