I had a flight from Taiwan (Taipei) to chiang mai 5 days ago (normal tourist) with thai lionair but i was denied to check in because i didnt have a ticket OUT of Thailand. Never had that problem before, is it new rules ? They made it very clear i would be denied to go on the plane without that ticket ( they also called up thaiimmigration office to check all my previous travels). Luckily i had time to order a ticket so i could get on the plane but what if i had been short on time ??