Most of this deals with people who leave a Random Team Lockdown game or get kicked from it.

1) Can anyone explain why it makes any sense to kick someone before they even get to the locker room?
I realize that the game is probably programmed to just kick immediately as soon as a character enters "afk" mode during a match; but, I've been kicked just because I was doing something else while waiting for a match to begin. I would have been able to get my knight to the gates before they openned if I hadn't been kicked; so, that team was unnecessarily made short a player from the very beginning.
Possible solution: Remove any "afk" status and reset the timer for it as soon as the player is taken to the waiting area (where the Devilites are).

2) Free-riders (those who don't actually play, but aren't afk)
I can only say for sure that this happened once, but I can see it becoming a bigger problem -- a player stayed in the locker room the whole time, had 0 captures, 0 defends, and 0 damage, but still got the crowns, coins, and rank points just for being there. I shouldn't have to play harder to make up for someone who decides to look at mail messages (or whatever), instead of helping us to win.
Possible solutions: Don't give any kind of reward if they have 0/0/0 points; OR, kick anyone who hasn't been outside the base's forcefield for whatever the afk time limit is, and give them that non-participation message.

3) Leaving during a game (the real losers)
I'm not talking about someone who gets disconnected, only those who click the "Return to Haven" button during a game. You would think that not getting any Krogmo coins or rank points would really discourage this, but right now it seems to happen at least every other game (not sure how many are really disconnects). Even for those that get disconnected, I've been able to rejoin the game I was in twice (you might have to exit and restart Steam before restarting Spiral Knights).
Possible solution: If a person clicks "Return to Haven" during a Lockdown game, they should be prevented from joining another Lockdown game for the next 1 to 2 hours.

4) Those that stick it out
To encourage people to stay, I think that anyone who is left on the losing team at the end of the game should receive 20 crowns for each person that left their team. (Why 20? I don't know -- just seemed like the right amount.)

5) Current crown bonus for when people leave is messed up
Normally, each player on the winning team gets 280 crowns. Apparently, the way it's currently set up, is that if anyone has ever left from the winning team, the rest of that team gets some bonus crowns. Here's an example where that system is obviously over-simplified: One person from my team, I believe, was kicked at the very beginning; a 2nd person from my team left about half way through, when it was pretty obvious that we wouldn't win; then, near the end of the game, one person from the other team leaves. So, even though they always had at least one more player than we did, they still got the bonus credits for winning. That was really "adding insult to injury" for those of us on the losing team.
Solution: Obviously, more factors have to be considered when determining whether to give bonus crowns. There are various levels of complexity that can be used, and I wouldn't even want to try figuring out the most complex of them. All I ask is that you don't give a bonus if the winning team was never at a disadvantage for the entire game.