Would it be remiss of me to yank open the door dressed in black with a toy axe covered in theatre blood and with made-up wax wounds all over my face?
I could switch off all the lights and wire up a halogen lamp pointing up into the house on the doorstep so it comes on when the door is open. A little webcam would have the dual role of capturing reactions and serving as an early warning so the very young can be attended by someone a bit less frightening...