1) The mudded screw holes in your garage ceiling drywall are actually lined up with a joist. Those screws may just be for show
(I was putting in a storage rack over the garage door and screwed the 2x4 along the line of screw holes in the ceiling drywall. When I went to test the holding strength the whole thing just popped out. Apparently the drywallers were off by about 5")
2) The lock switch on the garage door opener actually locks the garage door from opening. Otherwise, when you are standing on a ladder screwing in the 2x4 to the correct location you may suddenly find the garage door racing towards your neck in an effort to decapitate you when your wife arrives home early
(I was putting in a storage rack over the garage door and screwed the 2x4 along the line of screw holes in the ceiling drywall. When I went to test the holding strength the whole thing just popped out. Apparently the drywallers were off by about 5")
2) The lock switch on the garage door opener actually locks the garage door from opening. Otherwise, when you are standing on a ladder screwing in the 2x4 to the correct location you may suddenly find the garage door racing towards your neck in an effort to decapitate you when your wife arrives home early