I think we can all agree that accidentally leaving your garage door open over night is a security risk. Adding a contact sensor, however, is not the best solution. If your system is armed and you open your garage door on arrival to your home, the countdown to disarm will begin. If you don’t disarm in the short time available…the system will notify authorities.
My suggestion is to update the ‘Placement’ settings for the sensor. Currently there are only 3 options - Main Door, Secondary Door, and Window. I suggest you add ‘Garage Door’. With this setting, you will be notified if the garage door is open when attempting to arm the system. Just like if a window or door is open, you will have to bypass the sensor if you intend on arming with it open. At least at this point you will know the garage door is open. However, opening the door should not trip the alarm. If your system is armed and you arrive home through your garage…it doesn’t start the countdown to disarm. Nothing should happen. Again, the intent of the sensor is only not notify you that your garage door(s) is open when arming.