Livy records that geese kept at the temple of Juno on the Capitoline Hill alerted the defenders to a Gaulish night assault, conventionally dated to the early fourth century BC. The story is legendary in its details and cannot be verified, but it reflects a genuine and long-standing use of the birds.
The behavioural basis is real. Geese are highly territorial, have excellent daytime and reasonable low-light vision, and respond to unfamiliar movement with loud, sustained calling. They cannot be quieted with food in the way a dog can, and they do not habituate readily to a familiar intruder. Flocks have been used to guard perimeter fences at military sites in several countries, and Scottish whisky bonded warehouses have kept geese as watch birds.
The limitation is discrimination. A goose alarms at anything unfamiliar, including wildlife and weather, so the signal carries a high false-positive rate. What geese provide is a cheap, self-maintaining and unbribable noise sensor, not a judgement about whether the disturbance matters.