There are (I think) ways to tune the sensors so they won’t pick up smaller animals, but will still grab larger beings even if they’re moving slow. As to recording, if you have broadband, I suggest setting up a link such that if the cameras go on, the recording server starts a real-time mirror session with someplace off-property. That way you have a “safe” copy of the video recording even if the cops grab the onsite drive. Once the off-site recording stops, it should be easy to have a script launch that makes duplicates of the duplicate. Keep the session on the remote drive, but also burn at least 2-3 copies of it to DVD, and arrange to have at least one mailed to an attorney you have on retainer.
It might seem over-complicated, and it shouldn’t have to be on the citizen to make such extreme preparations, but in the face of the increasingly-unaccountable actions of law enforcement at all levels it is almost a necessity these days.
Sounds like a good idea for anyone, in these days of no-knock raids on wrong addresses. You can bet they would seize and destroy the security hard drive. I can access the drive over the internet, but not after the fact if it's taken. However, I think I can mirror it to my laptop, and the laptop is constantly backed up every hour to a network drive. This backup destination can be pointed to an offsite location. Thanks for the tip.