They should really get a lock box to make sure travelers can leave, and the place is secure, they should also get cameras so they don’t have to constantly accuse travelers of things that didn’t happened during the duration of their stay. And if you’re going to lock the main gate that travelers need to access the main point of entrance you should teach them how to properly open it, so that they are not stuck outside at 3am with all their belongings inside your home and them not knowing if they ever get inside, them also not wanting to be super inconsiderate and ringing the door bell that late at night, just for them to be accused of things that didn’t take place the following day after leaving everything the way it was found...Thanks