Honestly, people who INTENTIONALLY go AFK in a ranked game, should get banned, no question. Or at the least Riot shouldn't make the team with the AFK'er lose ELO.
Last game, My team had this game in the bag. Our Vayne, who just complained the whole game about people doing bad, told us she was going AFK. Then, she came back. She said "Yea I have a GA now so i don'g get fountain dove" and AFK'ed again.
I just think either we shouldn't lose ELO for this or that player get banned right away.

Happens to everyone, move on.

Report them after the game. Once they get so many reports, action will be taken.

How do Riot know that it is really a intentionally AFK ? Remember ELO come right after the game, Riot can't do anything about ELO for a match.

And if they do, whenever you know you lose, you just have to convince someone in your team to afk. This is not fair for the other team and not the way it should be.So its not the best solution don't you think ? :s

Report them. If they say they're going to AFK, just wait for the system to punish them. It will take a little while, since the tribunal takes multiple reports across multiple games, but it will happen. It they don't explicitly state that they're going AFK, it's going to be very difficult to determine if it's intentional, accidental, or an emergency.

In short, don't blanket ban. Just report and move on.

People that shouldn't play ranked play ranked. They get beat so much that they don't care and just decide to leave. Tell everybody to report for afk and that it was their decision to leave. The tribunal should all punish.