If a phone no one came up, he should call the police, said that when he arrived, the door was open, and you're at work and could not close it did not, while he calls her name and address, and only upon the arrival of policemen he may enter the apartment. True, the child may forget about your warnings and will open the door for what you are home, but ran out the garbage or just forgot to close the door, and then he enters the apartment, at the risk of becoming a victim crime, because if the apartment thieves, they can cause a variety of injury to a child who does not even know about the attack. An open door may be perceived as a sign of his child or your forgetfulness, when you or he went away to work or school, you just forgot to lock the door, especially if such cases have already been. But do not just open the door alarm for your child, but also to collect things, and just clutter in the apartment. Your child may itself open the door, especially if the lock closes, and entered the apartment to see other people's bags or boxes forward. In this case, it is better to go to the neighbors and call home, if his calls no one answered, call the police and tell you to work.
And do not worry, if you collect stuff, who decided to throw out, or you have guests, and that their bags are in the corridor, and the child went to the neighbors to call it a proof that he clearly performs its own security rules. And do not deride it, because next time it could safely enter the house when there are criminals. We give two examples, both cases occurred with the same kid, just the first 'Lesson' went for it in vain.