Firecop203's comment spoke of perhaps there being a second vehicle on the street to "judge" the reaction. That way, the actual "perpetrator" would be gone if the homeowner happened to have video of their own with which to "identify" the suspect.
There was a report a month or so ago about an incident where a home invasion was thwarted by the lady of the house having a pistol. They were hoping to get an arrest from images/video from an outdoor trail camera. Maybe it is time to install one at one's home? Perhaps high enough that the thieves can't steal the camera?
True, but the only reaction a spotter vehicle might observe is whether or not someone opened the door. Many people would look out their peepholes and not bother opening the door is they didn't see anyone,therefore if you knock and run away you haven't really determined if someone is home. (well, I guess being late at night they could observe lights coming on.)
I loved that trail camera idea, so much simpler than a home video system...I'm using one now.