Our family has ties to Virginia Tech, so when I see someone wearing anything with a VT logo on it, I take a careful look. I spotted this cute young lady walking toward me outside Martinsville Speedway, and waited until she got within the frame I desired, and then I clicked the shutter as she walked past. I used a small camera so she was not aware of what I was doing, but even if she had been, I suspect she would have smiled even more.
This brings me to the subject of taking candid pictures of people…like do you need to ask for permission first? Answer is no, unless you were perhaps doing so with some commercial purpose in mind. Having said that, it’s my usual habit to ask if it’s OK, if the person sees me taking their picture. I try to be as friendly as I can, and usually show them the result on my camera’s LCD monitor afterwards. This sometimes leads to more conversation and perhaps some more photos. But, the bottom line is that what’s called “street photography” is usually totally candid and anonymous.