I'm sure there is some looney lefty law over here, or some daft petition by the tree hugging brigade that will jump up and down and say "It's bad for the environment and it will kill all the plankton in the seas and world will stop spinning on it's axis if you let your engine run without being in the car"
I believe there is a nanny law over here that states you cannot leave your car unattended with the engine running. I don't agree with any of the above crap and if I want to start my car remotely to warm it up on cold winter mornings I should be afforded that option.
The Ed
You cannot leave it with the engine running on the highway but in your drive possibly. However if your car is stolen whilst standing with the engine running, your insurer might well refuse to pay out.
Don't think there is anything in most policies about engine running? The usual criteria is car must be locked and keys not in the ignition, which using a remote start device would satisfy both conditions.
If in doubt, sue the b*stards and they will pay up !!