From my experience, the disconnected battery/no-start problem has to do with the key vs. spare key. The car must "know" which key was used before the battery was disconnected. I think the thing to watch for is the alarm light on the dash, the lcon with the pad lock symbol apparently tells you when a key is locked out.

Anyone want to do some battery disconnect experiements to indentify which combination of key/disconnected battery leads to the no start condition?

 

Oh yes, this I am familiar with. And I have set it off several times, in my Monte SS and Silverado-not yet in the HHR, noisy yes, theft deterrent probably not.

I hear them often in parking lots at malls etc...