This does work!
I know because someone tried to steal my car a few weeks ago and this stopped them. I dunno how they got in, but at quarter til 3, i was awakened by the car alarm and I had time to figure out it was not a false alarm, and get up and get dressed and then go outside and he jumped out of the car and ran. He hed been trying to jimmy the column but this Steadfast collar kept it from being stolen.
My car has an alarm, this thing, and the Ravelco device to keep it from being stolen. I'm going to get a gun next.