Strange, I just had a flat with my Dunlop tires. My HCH has around 9000 miles, and I just returned from a cross country trip. I left my office, noticed a bit more noise from the back than usual, but the car handled fine, so I didn't think anything of it. I stopped for gas and noticed the tire was flat. When I put air in it, a bulge appeared on the tire, and it deflated again after a few minutes.

I'm not sure why it went flat, but it seemed defective to me. The folks at the tire store told me those models of Dunlops are hard to come by apart from the dealership, so I ended up with a Yokohama instead. Seems awful early in a car's life to have a flat tire.