Besides being considered grossly inconsiderate, ignoring handicap signs in parking spaces can also get you into more trouble. Handicap signs aren't put there for no reason. Because of the limited mobility that many handicap persons are faced with, the need these parking places for easier access to their destination.
Just as those with handicaps need convenient parking areas, they also need access to convenient restroom facilities that are easily accessible. When you are constructing a public restroom it is a given that you will make proper accomodations to suit handicapped needs. keep in mind, however, that just building them isn't enough, you also need to label them.
*When choosing restroom signs don't forget handicap restroom signs. it is important that these signs are easy to read and in clear view.