Yesterday Niantic announced to take action against cheaters and trainers who are trying to use unfair ways of getting advances in Pokémon Go.
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.
There have been many tools out there to level your account automatically, to spoof GPS locations etc. During the last couple of weeks niantic already started banning IP addresses which were calling the API too often. How does that work?