Cheaters never win, well at least not in Pokémon Go. A new three-strike discipline policy has now been put in place by Niantic. The new set of rules, posted via Niantic's official site, is meant to curb cheaters who falsify their location via GPS spoofing, side-load Pokémon with dubious methods, or utilize third-party software and add-ons. This new system is meant as a chance for offenders to "learn from their mistakes" and "change their ways," according to Niantic.
The first strike is a warning, and you'll get a special alert within Pokémon Go if you've been caught cheating. You won't be able to encounter any rare Pokémon during a seven day probation period, and you may not receive any new EX Raid Passes. These privileges will be brought back after the warning lifts, but Niantic says your privileges "may" also be removed. It's unclear which offenses will cause these changes to take place.
The second strike is a suspension. If you receive a second warning, you'll lose access to your account, and you won't be able to bypass the onscreen suspension message. This is a 30-day ban. After that, you'll be able to log in again.
The third and final strike is the most severe, and if you get this far, Niantic will ban your account outright. This ban will be permanent. There is an appeals process you can go through if you believe you've had your account wrongfully terminated, but Niantic states that "very few" terminations will ever be overturned due to its systems' "high level of accuracy."
If you're planning on cheating in Pokémon Go, consider the risk. And the spirit of the game. But if not that then certainly the risk.