Can the average person use their mouth to generate enough vacuum to open the door locks?
Don't get into the habit of opening the rear door to lock the car instead of using the key. I do that sometimes and one time the keys fell out of my jacket onto the seat and i locked myself out.
Had to make a sharpened hook out of a coat hanger, pry door open slightly with a long screwdriver and leather to protect the paint, and hook the button. Takes less than a minute if you have the theft tools. Too easy to break into these cars IMO.