I had flew a week ago from Rome to PP without visa with Singapor air with one way ticket and had with me one real ticket bought with Airasia to go out from PP to Bkk not within 30 days on my arrival. At the check in: 1st asked me if I had visa,I showed that i do not need,2nd asked me if I had flight ticket to leave the country, so I showed my PP- BKK ticket but after a while she started to say that their system was saying that my return ticket must be within 30 days from the date I land to PP and told me that she could not let me board on the plane unless I was buying another ticket, so I told her to call the supervisor and explain that Cambodia immigration do not really require all that bulshit airline ask me for with real proof but she insist to say they cannot take any responsability so she called here in PP airport to the main officer in charge and asked him my nationality,passport exipre, name and if I was in Cambodia before. Anyway after standing aside for 30 minutes the supervisor received a message from PP to accept me on board.So all depends from the staff at the airport and what their system say. so I reccommend saving with you all the update requirements Cambodia immigraion from local source as I did to show . Funny that in PP airport nobody asked me anything and when I asked for ordinary visa they were charge me $30 but not having any surprise collecting my passport I told the price was $35.