While another guard event is possible, getting that from Kuri-chan isn't a sign of anything. That's always in her loot table. Heck, its one of the first things I got when I fed her the first week of the game. Got a bunch of drinks, elixirs, glasses and compasses before I even got anything worthwhile out of that thief.

JP players seem to be leaning toward it being a tower event though, where the slayer cards boost your points which overall ranking is based on.