If someone has mentioned this before my appologies, a quick scan of current threads didn't turn it up. I'd classify this as an Andy Rooney / Cliff Cllavin little fun idea.
It just occurred to me that when taking in a map in an esc game, especially on one with darker backgrounds such as classic, the pattern of a player who is both weak and proximate is more readily apparent for opponents with bright colors such as yellow and teal.
It would be interesting to see if there is any bias in the stats that shows winning an esc on a dark map is more likely for green or blue, or, especially of late, slate.