@Chantelle *****
I see a lot of reasons why it might not work. The history of 6 months back to back visa exempt you can hardly call touristic use. Tourist might travel for longer periods, and return to tjhe same country every now and then, but tourist don't do border runs.
Once warned will mean chances IO checks next time are high. With a good story, hotel reservations and return ticket it might work.
Topic starter does not tell his real reasons for visiting Thailand, but I don't believe it is just as a tourist, and an IO might also think that way.