When I talked to him about it the first time, he didn't really seem to give too much of a damn about it. And he's sort of a pretty boy, my car is too cool kind of guy who probably thinks it is neat his car does that. For example, he also has a remote start and will use it to start the car as he walks out to it like 5 seconds before he gets into it!
As for 911... if it ran continuously I might call the police, but not 911. Irritating thing about it is, it runs for 30 seconds and shuts off. It is bad enough that it goes off, but when it does, instead of turning it off (even if he is sitting in his living room watching TV) he justs lets it run through its whole 30 second cycle. It might do it 3 times in a row and he would ignore it. That's the habit I want to break him of =)
Plus building things is fun!