Originally Posted by
orbitmic
The authorities will decide how to return you where you come from, typically on the career that brought you which could charge you or just use your return coupon. If no flight or they are full, authorities will decide to either let you ina hôtel for the night with an obligation to return for your flight, let you hang around in the transit zone or place you in the custody of immigration authorities until you can be flown back (not nice)
I've always had the impression that the carrier is obligated to return the person even if doing so means that they must VDB/IDB another passenger. However, in the case of Russia, they might need to be sure to pick someone for when the additional day would not mean an overstay of that person's visa.
Also, if the carrier doesn't have a flight returning the same day (which I suspect is generally not the case for Russia), would the carrier be obligated to rebook the person on some other airline?