The most common mounting location for power at garage door openers is a ceiling mounted box overhead. This is almost exclusively the case for drywalled garages.
The shipped power Brick has nothing to secure the brick except the strength of the receptacle contacts against the prongs themselves. This is an accident waiting to happen, especially given the minor vibration involved each time the door is operated, or installation with an older receptacle that may have worn contacts.
I would think the ideal case is a wall wort with a longer screw that can replace the center cover plate screw and secure the whole thing to a duplex receptacle, while leaving the other receptacle open. My old alarm panel had a power brick like this. Failing that, at minimum include a strap to prevent it from falling out, damaging a car, and resulting in a bunch of small claims lawsuits!
