A few years ago, we had our smoke detectors replaced. The person who replaced them used all the same locations and electrical hook-ups, except this one. Can I just remove the plastic, patch the wall and paint.
Reason I can't go back to the source: done by a home security firm that we no longer use. As soon as they finished install and started instructing us how to use it (oh, you have pets? Well, you'll have to turn off all the motion sensors every time you set it. The dog barks set off glass break sensors? You'll have to turn those off too.) We started looking for alternatives.