He was out riding . . . that's good enough, isn't it? There's no requirements that you ahve to wear a cycling-specific jersey. I wear t-shirts here in Southern California because I find cycling-specific shirts are not really comfortable. They're either made with open weave fabric that lets the sunshine through, giving me a nice sunburn, or made of tight-weave poly fabric that gets a little too 'muggy'. A t-shirt seems to collect the warm sweat, the 15-20mph breeze I create while riding cools it off, and it cools me down. I'll wear the tight weave one in the winter, but summetime is t-shirt time. It works for me.