I decided to test Riot's intentional feeding detection, here are the results.
It was a normal Blind Pick game, I mostly only used chat to talk to enemies, no flaming my team that i can remember. http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2563261443/45970599?tab=overview I locked in kayn after our taliyah already called midlane, rushed mobis +e to feed faster running down mid then every other lane. The few kills I got were from enemies overstaying and fucking around with like 20% hp. I actively dealt damage to enemies and minions. I also took the Shadow Assassin transformation. My team tried to be positive and encouraging but it was useless and we lost at 29:30. Funny, that game took longer than some of my ranked games. Anyways, this game caused me to receive a 2 -week suspension 5 days later.
Conclusion: Riot's intentional feeding detection actually works, atleast if it's an obvious case. Glad that they're stepping up their game considering that when I started playing 3 years ago, I int fed 12 ranked games in a row with no punishment.
Feel free to bring your own cases of int feeding/others int feeding, I want to see if it's consistent. Also: Don't try this experiment on your main, probably not worth it unless you dont care about hextech loot like me.