Niantic has announced that it will be cracking down on players who are using 'illegal' methods to obtain their favourite monsters in Pokémon GO, and players are starting to notice that their prized collections have been rendered useless.
A tweet from the Japanese Pokémon GO Twitter account has stated that measures will be taken against any actions that affect normal gameplay. In particular, this is aimed at the use of third party services which can be used to manipulate the game, violating GO's terms of service in the process.
As it turns out, the measure Niantic is taking is to simply remove any illegally obtained Pokémon from the game. Or at least, that's kind of what's happening. As you can see from this reply below, the Pokémon remain in their original positions, but are replaced by a diagonal pink line that seems to act as a reminder that you've broken the rules. Creatures marked with this pink line become pretty useless as they can no longer battle, earn candy, or be used in any other features in the game.
We can't imagine this deterring players from trying to find workarounds, but hopefully this should create a more even and fair playing field as Niantic suggested.