I can certainly understand Starch1ld's frustrations about low turnout and I agree with AlphaCat. I like the idea of organized TC a lot, but if there aren't enough people for TC, then we play TSA/SA until such time as there is enough. For me the fun part is being able to voice chat (effortless exchange of intel, strategy, small amounts of general bullshitting) with the entire team during a game, no matter what type of game that is. Everyone can type, and certainly everyone can read in-game text chat, but for some inexplicable reason people are just more "together" when they are in voice chat. In that kind environment, I'll do weight-limited drops TSA style, TC, SA, hell even sparrowhawk duels.
What I think hurts turnout a lot is that although a password protected server is great to ensure that only people that are willing to play ball can join, there's no easy way for people to see how to get into "that one server with all the players that's got a password on it". If you don't happen to cruise the forums, and therefore don't already know what's going on, all you see is server filled with people and a big, fat padlock on it. I can understand how one in that situation may feel like it is unnecessary exclusion, especially with a player base that is relatively small. Word-of-mouth helps; with people who do know about events typing out announcements in chat on other servers. That helpfulness lasts precisely as long as it takes for those people who know to join the locked server to actually play. Then the announcements stop.