If an airline transports you to another country try and that country refuses to let you in because you do not have a passport then the airline must transport you back. That's why the airlines closely check your documents before letting you board. So, the likelihood is that they would not have let her board. However, there have been instances in which a passenger was able to convince an airline to let them board and then try to oursuade authorities to let them in after they arrive. I wouldn't bet on that happening - but that's what she would have been facing had she not found her passport. So...is your sister really good at sales?