Other than a fortified bunker with no windows, I doubt there are many houses that could not be easily entered by the FD or PD in an emergency. You might need to replace a window or a doorjam after entry, but that is a minor deal in the big scheme of things. My son accidentally "entered" our house the other day with a misplaced slapshot - the hockey puck went right through the window without encountering any formidable resistance!