Cheating in any game is a common thing, so as expected there are many cheaters in Pokemon GO. When the game launched it was public knowledge that cheating would result in a soft ban. This meant that you will banned from playing for a few hours. Well now it looks like Niantic is stepping things up and handing out permanent bans to players who are found cheating.
This means if you are caught going against the games terms of service by using things like GPS spoofing, bots, emulations, and so on, your account will be banned for good! Here is the full details on the permanent ban directly from Niantic:
Your account was permanently terminated for violations of the Pokémon GO Terms of Service. This includes, but is not limited to: falsifying your location, using emulators, modified or unofficial software and/or accessing Pokémon GO clients or backends in an unauthorized manner including through the use of third party software.
Our goal is to provide a fair, fun and legitimate game experience for everyone. We will continue to work with all of you to improve the quality of the gameplay, including ongoing optimization and fine tuning of our anti-cheat system. If you believe your account has been terminated in error incorrectly, you can appeal that termination through this form. For privacy reasons, please do not post appeals on social media.
While the permanent ban is a little harsh, it is a great was to keep things fair for everyone out there.