The guests might even conceal themselves from view, and when the honored person enters the room, they leap from hiding and all shout, "Surprise!" For some surprise birthday parties, it is considered to be a good tactic to shock the honored person. Streamers, silly string, and balloons may be used for this purpose. Evidence of a party, such as decorations and balloons, are not made visible from the exterior of the home, so that the honored person will suspect nothing.