There is no guarantee with this registry of positive outcome. What the registry allows is the ability for patrol officers to have necessary information faster to begin searching. Also, if an officer comes across a "wandering" child who is unable to communicate, the officer, if they recognize the condition, can have the database queried for persons on the registry that live in the area.
What is important to stress is that simply having a person registered with the registry is not going to change police responses in every instance involving an individual with ASD. Police will act according to procedure depending on circumstances. An individual with ASD can still be arrested. In that case, being registered will assist police in contacting the correct people.