lighthouseI honestly haven't studied light enough to know what kinds of UV radiation tans you and which don't but saying UV is blocked by glass isn't entirely right
The only type of UV that isn't blocked by glass naturally is usually blocked by a coating used on almost all modern windows. It can degrade over time, but they can usually afford 99% protection new. That is also the UV that causes aging and cancer, not the one that tans.
I apologize for my generalization but I think arguing over a few percent and blaming it on your lack of knowledge is pointless.