I remember reading about a scam that is ongoing with night trains where someone posing as an authority figure knocks on a cabin door and asks for your passport and then robs those in the cabin.
I told this to my daughter and it got her into some trouble recently as she would not open the sleeping cabin door to show her passport. She misunderstood me and and did not realize there would be actual legitimate border stops with police asking for passports.
I feel like a fool and now I cannot find anything to support this. She'll never believe me anymore! Did I imagine reading this?