Garage door wide open? at 2am?

Seems suspicious enough for me to expect the police to have a closer look. Meaning it sucks that you got sprung because of it, but great if someone had broken in and the cops saved the day. Can't really fault them on that.

Not much else to say, you know you were wrong for taking the car. The police part is unfortunate, but next time you'll be more careful to keep things looking 'normal and orderly' so as not to attract unwelcome house guests.