I'm sure we have all been there ... we wait 30 minutes for a lobby to fill and when that last med/heavy final joins the ready up screen pops up and you watch as 10 player then 12, then 13 ready up. But wait!!! it stopped at 14 or 15 and now we are stuck waiting for engies and meds again.
I don't know if this is a result of people joining lobbies and then forgetting about them or people trolling but it would be nice to see something to prevent this from happening. It could be as simple as a second reliability score that instead of going down based on the number of times you leave a lobby that's already started, it would go down based on the number of times you fail to ready up for a lobby.
Another option would be for the site to just track it "quietly" and if it happens say ... 5 times in one week period they are banned for X days from using TF2center. If it happens again they are banned for X+2 days, and so on. The bans reseting down one level for every 2 weeks initially and then every week after the first two that they go without failing to ready up. This would ensure that someone who just stepped away from their comp to use the bathroom, or go outside for a smoke would not be penalized because it would only happen once in a while to them but would discourage people who habitually do this and would stop people who are doing it only to troll.