As you may have already heard, those found cheating in Pokemon GO will have their accounts terminated. Developer Niantic has issued a statement regarding cheating and bans in the game, which you can read below:
After reviewing many reports of in-game cheating, we have started taking action against players taking unfair advantage of and abusing Pokémon GO. Moving forward, we will continue to terminate accounts that show clear signs of cheating.
Our main priority with Pokémon GO is to provide a fair, fun, and legitimate game experience for all players. If our system has determined that you cheated, then you will receive an email stating that your account has been terminated.
Pokémon Blog 