AND THIS is part of the reason we installed a hotel bar on our door when our son was young...... 
I don't know how many times we've told our neighbor he needs one because their little one takes off all the time and runs down to the street where people can't see around the corner as they come around it. 
HOW HARD IS IT to make sure in some way that a kid can't get out the door? REALLY...How hard? For us it cost a few dollar and about 10 minutes. Our son NEVER got out by himself. Hell sometimes I don't because that thing makes such a loud sound!