System for afk players

Recently, I was playing a draft match, everything was normal within the first 2 minutes. After those 2 minutes passed, I noticed that we had 2 afk players, after noticing that, another player from our team had left. The other 2 afk teammates never moved so I decided to abandon the match, it was hopeless. I talked with someone from the Riot Support Team, I asked him/her (his/her name shall remain anonymous) to create a system for afk players instead of just reporting them. I was suggested to post my idea here. I believe that the system would simply warn the player that has been afk for over one and a half minute that he is going to be kicked out of a match. If the player doesn't leave the "Spawn area" or "Shop" (I don't really know how it's called) within that time, he will then be kicked and be replaced by a bot (intermediate difficulty).