Scores like 0/9/1, 2/10/4, 1/16/9, 7/24/4 etc should be automatically put on the int-feeding watchlist. I'm not saying punish them immediately, but when a player clearly isn't trying to win and just goes in repeatedly on a toplaner (or midlaner) that is 3 levels ahead while saying in chat 'idc first time irelia xDDDD', or doing braindead 1v3/4/5 engages all the time when there is clearly nobody else around to follow up (hi yasuo), that's clearly inting, even if they 'fight' instead of just standing around by a turret waiting for someone to kill them. Not all inting is the blatantly obvious all-chat spamming teemo jungle with ghost and teleport. But it is still very easy to spot if you know what to look for.
Meanwhile say 2 words in chat to them for wasting 35 mins of your time ('stfu %%%%%%' for instance) and you can get your account chat restricted. That is kind of a double standard, but back to my point. Obviously there are exceptions such as a 50+ min game where you are expected to die more often, but in every other case nobody should be dying more than 15 times in a game, like, ever. And 16+ deaths in a game is a sure-fire red flag in EVERY Divison. But I almost never get an instant feedback report verified after reporting someone for inting unless close to all 9 players report.
Cmon Riot I know you don't want make it seem like you're forcing people to play better but trolls really aren't that hard to detect. Tighten up your algorithms please.