I recently heard that some airlines refuse to let you fly to Japan (from Europe), if you don't have a return ticket. Since it is possible to buy one-way tickets, I guess this is utter nonsense, but just to be sure I wanted to ask anyway.
Is there anything that might prompt this (supposed) urban legend? Any grain of truth?
Bonus: What about other countries?
Update: Just occured to me I might add my experimental data point to this. Of course I might have just been lucky, but I had a one-way ticket (Emirates) and I had no visa at the time, was not refused boarding, and was also not refused entry in Japan. I don't really remember now, but I think they didn't even ask me a lot of questions at immigration.