Blizzard are continuing to combat cheaters in Overwatch, and while most games that are played don't contain cheaters the ones that do will now be shut down upon detection.
In the most recent Overwatch developers update, Blizzard Overwatch icon Jeff Kaplan sat down to discuss the more harsh punishments being introduced into the game. According to Kaplan, "the next evolution of cheat detection" will be that once the game detects that a player is cheating it will automatically shut down the entire game.
Players that are not cheating will not be penalized in any means, whether or not they are on the team with the cheater or not. This means that for competitive matches players won't have to be concerned with loosing SR if it appears there is a cheater on the other team. Blizzard seem to be cracking down on cheaters in Overwatch and Kaplan says that "very harsh actions are happening" to anyone who Blizzard finds to be breaking the rules.