Thank you for your interesting comments. For me, the main reason was "size" being far more generous than Thai equivalents. When I lived in Lanna, I made regular shopping trips to Maesai and crossed the Burmese border into Tachilek. The large duty free shop in Tachilek was stacked with "designer labelled" clothes such as Lacoste, Boss, Armani, Cardin, Hilfiger etc. etc. at a fraction of the price in the local Thai Central Plazas. Of course, they were copies but the quality was there and a large meant large, not a Thai "tight" large!! Never a problem with Customs bringing them back into Thailand - all run by the local Burmese/Thai mafia along with the casinos. I still have shirts and sports trousers here with me in Cambodia purchased around 6 years ago. No singlets/shorts and flip flops for me!