The DROP DATABASE IF EXISTS, DROP TABLE IF EXISTS, and DROP VIEW IF EXISTS statements are always replicated, even if the database, table, or view to be dropped does not exist on the master. This is to ensure that the object to be dropped no longer exists on either the master or the slave, once the slave has caught up with the master.

Beginning with MySQL 5.1.33, DROP ... IF EXISTS statements for stored programs (stored functions and procedures, triggers, and events) are also replicated, even if the stored program to be dropped does not exist on the master. (Bug#13684)