I was accustomed to see the Trojan Horse as cunning, but only after re-reading Aeneid II very slowly did it become apparent that it was above all daring – a last, desperate, long shot gamble that paid off. The Greeks built the horse and simply left it on the beach, retreating to a nearby island to watch what happened. One option was always that the Trojans would see it as a trap, or a bad omen, or something to be otherwise destroyed or abandoned. Had they destroyed it they would have discovered it was a trap, which would leave the Greeks discovered and with no foothold on the land any more.
True, in Vergil’s telling the Greeks got several lucky breaks (Laocoön, the main proponent of destroying the horse, was eaten by a serpent, and this was taken as an omen), but the suggestion to take the horse was flying about the population long before this happened. The Greeks, it seems, were counting on the human desire never to turn away something free or there for the taking, which they took as strong enough even to overpower our suspicion of those who just yesterday were trying to kill us. So perhaps they made less of a gamble than one might think.