Many of the new GM vehicles have you disconnect the battery for a reason. It's not all about the battery going dead from things being left on. It's also about the new generation of electric steering. When the battery is left connected, the electric steering stays active and can fight against being towed, ruining the steering. Many of us bought the newly restyled Chevrolet Colorado and GM Canyon pickups when they came out in 2015. They're towable, but require that the battery be disconnected. Many have tried to figure out how to disconnect the power to the electric steering, but no luck and GM isn't saying anything.