Is there a way to deal with "covert" trolling? Do report descriptions have any effect?

A game like this : we re struggling but manage to go pretty even, carries are fed and things are looking optimistic but our top laner lost his lane and died so now he wants to surrender. We refuse, game goes on, then we lose a fight and he wants to surrender again ( the game was not lost yet, we didn't lose anything critical ) we refuse again so he decides to troll. Doesn't say anything in chat, but starts to mindlessly walk down a lane/alone into the jungle and jumps the first enemy he sees, doesn't matter if there is vision, if enemy is alone or 5, he just jumps in ( got 1 or 2 kills that way I think ) ignoring every call or ping to go back. Every single time time he would die, respawn, and do the same thing over again while trying to surrender in the process, until it was late enough for enemy team to easily take baron and end the game. He didn't say a word or buy any weird items. This all happened in about 10 minutes.

Ofcourse I reported him just like the rest of the team but it got me wondering, do these people even get detected by the system? Basically half the game playing normally, no weird items, no toxicity in chat, yet he completely trashes the game in his intent. I tried to describe it the best I could but the punishments are automated so I wonder does it even matter ? How is a bot gonna evaluate what I described? It's not the first time something like this happens, it's infuriating to deal with yet not as explicit as a teemo buying 5 zeals and going 0 30.

If there are any rioter comments on a similar case I'd appreciate if you linked them