"normal precautions (locking doors, windows etc..) are not really effective"
My heart goes out to you if you are one of those rare parents of an autistic child who wanders. Did you know that there are door locks that have a key rather than a knob on the inside? You just put the key out of reach of your young child and the wandering problem is solved. See? You can do it yourself without government help. When you need a helping hand, the first place to look is at the end of your arm.