Yep... we know where we live... some things never change, others can change quickly. Also the DTV was actually an idea from the old PM... for some politicians that would be reason enough to cancel it.
Yep... I totally agree... for years now they are talking about "quality tourists", and now they do this... that's unbelievable. About changing... the next fun will start in january... when the first people try to get an extension. Let's see what will happen... maybe the border bounce shops need more vans then... ;-)
Seems quite expensive to me... the prices for cooking classes went up a lot since you can use it for DTV. You might consider Muay Thai... there was one guy in Bangkok who booked 20 hours within 2 month for about 6,700 Baht. I probably have the post somewhere...
They warned you because you tried to stay long time without a real visa, they told you to get a proper visa. Why should they deny entry if you arrive with a valid visa now? Won't happen if there's nothing else shady in your history.
They are pretty relaxed about it at the moment, but there is no guarantee that they let you in on exemption forever. It's always "up to the discretion of the IO".