I feel more uncomfortable when the employee is much younger than me. Closer to my age, still uncomfortable, but not as much.
I have found the best time to stare at a chest, I mean read a name tag, is when the cashier is making change and their eyes are focused on the drawer. I often pay with a larger bill in these cases.
If I still don't get the name, I might get back in line when they are helping another customer, or I might just report I couldn't read the name without appearing to stare. I have never gotten any blowback from the MSCs.