A buddy of mine has two third generation night vision rifle scopes. I wanted to see how they worked so we went out jackrabbit hunting at night. I was really disappointed in them. If a man was standing out in the open, you could see him fine. If a rabbit was on the dirt road you could see it fine. However, if a rabbit was in the brush (sage brush) you really couldn't tell what was rabbit and what was brush, it was all just dark stuff in the scope. He also had a big IR flashlight, it looked just like a maglight that held about six D batteries. Using this IR light, you could see clear as day for about 15 feet through the scope. After that, it was just dark junk in the scope. Maybe if there had been more moonlight ? Maybe if we wern't out in the middle of no where with absolutely no other light ? We both got one rabbit a piece and it was a neat experience to be sitting in total darkness next to a guy then see a muzzleflash, turn on a light and see a dead rabbit.
I decided after that that night vision wasn't worth the money they charge for the stuff. I am sure that I could easily see the stuff in my yard at night. But if someone was using a little concealment and staying close to the ground, all bets are off.