Technically, it’s not a false passport. You are carrying a document that may look like a passport but it: [ul][li]Does not claim to be issued by a government.[/li][li]Will not be used as an official document.[/li][li]Has nothing, whatsoever, to do with Opal.[/li][/ul] The article I saw came from Time back in the 80’s (IIRC) featured a company that did just this. They quoted a state department official who said that this was not illegal so long as you did not use this as an official document (if you got away from a terrorist with the thing they would probably cut you some slack).
All this was, of course, pre 9/11; I have no idea what officialdom would think of it now (still it’s not a forgery–sort of like carrying a $30 bill with a picture of Edison on it).
Not defunct but ‘never existed’. There are over 190 countries in the world, can you list them all? Given my ethnic makeup (European mongrel) I would claim that I was from a small country in northern Europe (practically a city-state). Maybe it would work, maybe it wouldn’t. Thing is, you have just given yourself a chance.
In the time period this came up (1980’s) there were a few events where a plane was hijacked and several passengers were set free (as a show of goodwill, to reduce headcount to a more manageable level or whatever). Hijackers are political animals who are protesting something—the nationalities of people who were least to be set free were Israel and the United States. Show some ID that you are from a different country entirely and you might get free.
I would consider this unlikely. You have an airplane with 100+ passengers and who knows how many bags, books, pouches, pockets or other places to stash a passport. The limited manpower of the hijackers is almost certainly not going to be spent doing a search. Of course I may be wrong but that is part of the risk: were you in such a situation you would have to ask yourself if it is worth it or not.