I entered Thailand in December on DTV, I'm an Aussie as well, applied for DTV out of Sydney and arrived in DMK. No problems, no questions asked, straight through. The immigration officer did hit up the guy before me asking how ling his stay would be. Maybe you're just unlucky and you were the 'random' person they'd scrutinize.
I'm very surprised that it turned around so quick. There was another guy yesterday posted he got the DTV from Sydney but it took him 2 (or close to 2) weeks.
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