Suppose that you are denied entry for a country but could not go back to the departure country for some reasons (already stayed for 90 days at the Schengen, cannot re-enter Vietnam for 30 days, etc...).
In this case, where is he/she going to be sent? Normally I think in this case, the next possible result is that the airline takes you to your country of origin, but not all airlines have the flight to any country. For example a Japanese citizen is denied entry at Minsk on a flight by Belarusian airlines, after staying for 90 days at Lithuania.
In this case is he/she going to be sent out to other places that the airline has the route (and the passenger doesn't need visa)?
And who pays the cost of the flight? I heard that the airline must take the responsibility of taking the passenger to the origin of the flight, but how about this case?