Guerrilla event

Guerrilla means 'war' (kind of), so what is this 'war' Event?

Guerrilla warfare is a form of irregular warfare in which a small group of combatants such as armed civilians (or "irregulars") use military tactics including ambushes, sabotage, raids, petty warfare, the element of surprise, and extraordinary mobility to dominate a larger and less-mobile traditional army, or strike an invulnerable target, and withdraw almost immediately.

So this event was/is indeed clandestine and quickly withdrawn. The characters I didn't accept it on (hit "esc") don't see it anymore, and new accounts I log in aren't getting it either. I don't know whether it was meant to be this limited in time, or was incorrectly activated today, or was intentionally a one-time chance for very specific accounts, or what. Ninja strike.