Why does the horn randomly beep twice at me?

This is due to the “ikey not found reminder”, this function can be turned off by looking in your owners-manual, page 4 item 5. When your door is opened and closed such as letting a passenger out of the vehicle and then the system sees an input on the brake wire the system will search for a key fob, if one is not detected it will beep twice. The key fob may be inside the vehicle but out of range of the antennas.