i agree. Technically it may not be a visa, but you have to get your passport stamped at the border. That itself works like a entry permit/authorization. I am aware of this, as my wife is Thai too.
the airline doesnt require it. The return flight ticket is asked by the thai immigration when you are entering. I have been in and out almost 4-5 times last year, and each time they asked for it at Bangkok airport immigrations. Then it was 15 days visa on arrival..
the purpose behind this new visa regulation was to promote investment and for people to bring in their money, resulting in increased expenditure within Thailand. The economy has not been doing well in the past year, and it needed a boost. This was one way to make foreigners bring in their money and spend it in Thailand. The more the merrier..!!