Can a train ticket from Thailand to Laos serve as proof of onward travel for AirAsia?

The question posed is whether a train ticket from Nong Khai, Thailand to Vientiane, Laos can be used as proof of onward travel when flying with AirAsia from Kuala Lumpur International Airport. Several comments suggest that various forms of travel tickets, including bus, train, or flight tickets, are generally accepted as proof of leaving the country. Users share their experiences, indicating that they did not face issues when showing onward tickets, confirming that a train ticket should likely be sufficient.