Generally a good way to prevent real inters and throwers is to just be nice to your team

Unless the offending players are sociopaths, it is really hard to make the decisions to throw/feed intentionally when people are generally positive and friendly. And no, I don't mean just saying nothing and doing nothing, I mean actively trying to be friendly and encourage your team. It also helps if the enemy team trash talks.

I say this from personal experience - I once had a smurf that I was trying to derank from gold to bronze. I didn't actively feed, but I didn't try to win on it either, mostly just played off picks like AP WW and AP Nunu. When people were nice or the other team trash talked, I found it really hard not to cooperate while the opposite could be said for people who were dicks right off the bat.

Eventually I did make it to silver 1 after a large amount of games and I just decided a faster and less subjective approach would be to afk. Obviously this was before remakes and that account has long since been banned.