Sometimes, no reponse to a direct question (I asked "Does this mean that the 50% awards will be stopped?") can exactly lead one to assume the answer. But anyway...

Thai is no longer a good airline, compared with say Singapore, Lufthansa, Emirates, Qatar, Cathay, Qantas, Etihad, BA... I could go on. I had already decided to "jump ship" form TG, with my last paid-for flight being next Thursday. However, one of the few things in TG's favour was its 50% awards for the 3 birthday months, which is why I even decided to make this last flight to re-qualify until Nov 2010.

But like you say, removing that birthday 50% miles benefit would probably only harm frequent fliers... like me. My company pays for seats on flights where there's no chance for me to use any upgrade. So spending my miles in some other way (on my personal flights) is vital. To have to pay for a ticket and use a voucher, means for me that airmiles are pointless/worthless. But this applies in large part to business travellers, and Thai Airways recently has demonstrated - to me at least, with my flights to/from Middle East - that it prefers families to businesspeople. You will notice this by the number of families they upgrade with babies. 2 weeks ago, Bangkok to Kuwait, 8 babies and 1 toddler in a noisy business class cabin. Even TG staff were surprised.

I suppose all of this detracts from the main point though. If you take something away that people value and are used to, you're gonna disappoint a lot of people very quickly