I've recently started playing CS:GO and I really like the way they act against people who disconnect and afk, they do the following
The first abandon has a 30-minute cool down, the second is 2 hours, then 24 hours, and one week. If you haven’t abandoned for a week you would cool down by one level (for example, from 24 hours back to 2 hours).
Riot also needs to try and find a way give loss prevention for afk matches if someone is afk from the start, sometimes isp's go down and what not.
Lyte has mentioned that there is a new system for AFKers coming in the near future. It will aggressively address AFKers. He often posts about this stuff on his twitter and will likely mention there when they activate the new system. Although, I suspect there will be an official announcement too.
