Addition to Team Builder - Leaving the Teams

Hello, I've played League for over 6 months now and I've poured over 1k games into the fray. Along the way I've experienced some of the many additions to the game since August. Team Builders release made finding a team, selecting who and what you want to be paired with, and able to delay the match until things are all neat and nice was a great addition.

However I have quickly seen a problem that I would like a suggest a fix to.

As a leader or Captain of the group, you might be waiting for 10,15, even 25 minutes waiting on a support or ADC (Hopefully not on both), Which normally would be okay, but players (Mainly ADC's or Supports) rather abuse their role. Many times, an ADC or Support will be accepted by the Captain, then leave rather instantly because the team does not yet have an ADC or Support. I find this "Cheating" the Que system. I (Nor does anyone else) want to sit in Que, then gracefully accept someone for them to instantly leave just because they didn't get into a full Que. Now my solution for the problem is rather simple. Why not give Team Builder a timer to help "Slow Down" Those individuals that want to speed through Builds looking for one that is already full. I personally believe that, once accepted, you should be "Stuck" in that Que, for lets say, 5 minutes. This DOES NOT harm you as a player if you are accepted by a troll group, champions you don't agree with, anything of that matter. After the "Lock Down" period, you then can leave without any offense to your account.

Now when I say offense, I mean the normal "Leaving to many Ques will result in a period which you can not search for a game". Does not mean that if you leave one, you will be punished with a 15 minute ban by any means. But it does mean that people who want to race through games because they think they are more important, or whatever the case, will have to at least slam on the breaks. Ruining and delaying other peoples matches and games just because there isn't a support in Que, is rather rude..

Thank you, I would love some feedback on this.