If there are multiple reports then please post a reference to say two.
Specifically an immigration official refused to allow someone to enter Thailand at a land border because they did not have a flight ticket to their home country.
Immigration have never asked me anywhere for outward, onward or return flight information. Sometimes they ask how long I will stay in the country.
Only some airline check-in staff have to tick the box. But never a return flight. A bus ticket, train ticket or flight to anywhere will keep them happy.
Come back and tell us whether immigration at the land border asked for specifically a return ticket to your home country.