If I could suggest a more environmentally friendly alternative to the claymores/ Semtex, the vans proximity sensor linked to a loudspeaker playing the sound of a Remington 870 wingmaster being racked. This WILL garner the full attention of the listener and initiate an immediate reassement as whether their current course of action is really for the best. If it turns out to be the postie or Cynthia collecting for the WI no bad.