Our hosts gave us detailed instructions to get into the apartment. The apartment was typical Venetian, very old- this was expected and therefore fine. It was not only jolting, but very uncomfortable when the previous nights guests returned to hang out, pick up baggage, and get things out of the fridge at about 1700. We current guests were shocked by their arrival into the apartment. We emailed fre hosts about this immediately but received no explanation or resolution. At checkout, we realized that there were not two sets of keys in the lock box, but four. this means that anyone who has rented from Irene and Leonardo can get back into the apartment at any point, undetected.