How many threads do we need on this? The coating is for RCS reduction because it turns the canopy into a smooth surface to a radar instead of allowing it to see the relatively high RCS cockpit. Not classified at all. Any "sunglasses" effect is a side benefit not it's primary purpose. Same reason they did it on the F/A-18s (both flavors), the F-22, F-35, and B-1B. The reason you see some F-16s with one tined piece is because they didn't have a tinted one handy when they swapped the the other piece out (for a clear front) or the aircraft didn't go through the upgrade (clear back). Pretty simple. I don't know why we need all these bull$hit explanations when it's not classified anyway. It's bad enough when people supply them out of ignorance, we don't them here on PURPOSE.