The inside story of Mark Kennedy, the police officer who lived a remarkable double life deep undercover, as environmental campaigner 'Mark Stone'.
The most important single factor in any 'orderly society' is predictability. Unless you are predictable, you are a threat.
If you are part of a group, expect to be infiltrated.. It doesn't matter whether you are discussing football, cooking, crochet, or politics.
They may not all be as cunning as Officer Kennedy, but they are definitely out there, and they will stop at nothing short of exposure to make sure that you are predictable.