KevinIsPwnI played in UGC for several months before learning p much anything about ESEA/ETF2L/TFTV/etc. I'm not the only one.
lol I watched a bunch of frag videos of top players for months of me finding out about comp tf2 and I though HL was THE game mode for comp tf2. I though these players (like ma3la, and grape) were UGC Plat 6s, when i found out they were playing 6v6 and not highlander.
part of the reason for my obliviousness was I saw lots of players in game with UGC participation and placement medals and so i just thought UGC was the place to go for comp TF2
anecdote aside, i agree with people like Kevin, new players aren't very likely to know what ESEA is