Niantic has begun sending a new acknowledgment screen to Pokémon GO violators and cheaters. The official statement from the developer is as follows:
Hey Trainers, if you have previously received a warning or suspension notice, you may see a new acknowledgment screen when logging into Pokémon GO. This is a one-time acknowledgment for previous violations and it doesn’t necessarily indicate a new punishment on your account.
Source: Niantic Support @NianticHelp