If you cheat a Pokemon Go, you could get banned for life.
That's the new rule of law being handed down by developers Niantic as they seek to even the playing field and make their game a fair experience for all. If you are found to be in breach of any part of the terms of service for the game you could find yourself unable to play.
You can read the full terms of service over here but the methods that can lead to a banning are pretty obvious: changing your location to spoof the GPS, modifying the software to make things easier or accessing the game data using third party apps.
Basically anything that is a very clear example of cheating. If you do that, there's a good chance you'll be tracked down and banned.
Considering that many people would use their email address to log into Pokemon Go, a full on banning is a pretty punitive action, and would see the player lose any progress they had made forever. Of course you could just start the game again with a new email address, but you would have to begin from scratch.
These measures also seem designed to prevent players from using third party apps like mapping software which could help them locate Pokemon in-game, which will have a knock on effect on those other websites.
If you do find yourself banned and think you have a case for appeal, click over here.