Goes to show you never ever leave the door to the RV unlocked even if just going to the bathroom real quick and never leave anything in sight. We lock our door even when just outside visiting the next campsite. We have a screen door hook inside the screen door just above the slide opening so the door can't be opened unless you open the little door and unhook the hook. Just make sure you don't close the outside door while it is hooked or you'll break the latch opening the doors. We put a large paper spring clasp on the outside of the screen clipping it in the hole for the outside door so we don't accidentally close the outside door while we are outside. We do this for safety so we can leave our door open at night when it is hot and to keep our pet from opening the door also. We also have an alarm that we can sit that is just a couple of plastic pieces that when separated it alarms. These are about $2-5. I'd rather be safe than sorry. Might sound extreme but we feel safer.