How laggers affect the game

I feel like people need to understand that playing with lag that prevents them from playing the game probably ruins matches. I feel like there needs to be a message or something to show people that they need to have a stable connection and can't risk games like this. If someone goes into a ranked match with constant lag cause they don't care but in reality can actually cause someone to demote or lose the ranked match cause of this single person making it a 4v5. There needs to be a system to fix this problem please.