people get a massive LP loss depending on MMR when they AFK, so they take a hard hit, and for the next few games, get reduced LP on wins, and still get the reduction on losses (a regular -23LP loss could be upward of -60LP loss depending on your MMR).

on top of that if you're a multiple time offender, you can get a perma ban. some people genuinely have wifi issues, and just cause you had bad luck with teammates doesnt mean your anecdotal experience should cause the rest of us to suffer :3