The bell tolls only once in Overwatch, and the bell tolls for che(aters).
In a forum post on Battle.net, community manager Lylirra stated that those caught cheating, using hacks, bots, or third-party software to gain an advantage will be permanently banned from the game. There’s no temporary system, warning, or even slap on the wrist: just immediate expulsion.
“Not only does cheating undermine the spirit of fair play that all of our products are based on, but it works to diminish the fun and enjoyment of others,” the post continued. “While we are unlikely to publicly acknowledge when accounts are closed as a result of cheating or using unauthorized programs, we have and will continue to monitor Overwatch for exploitative behavior, as well as take action as needed to preserve the integrity of game.”
There is an in-game option to report players for cheating if that is believed to be the case, although Blizzard definitely now has to be extra careful who they actually ban.
Overwatch releases on May 24th for the Xbox One, PlayStation 4, and PC.