^Maybe they would've seen the Star Destroyer and known it was a trap?
(You know, it's just now occurred to me, after 37 years, that "Star Destroyer" is false advertising. I mean, the Death Star was supposed to be the ultimate weapon, more powerful than anything before it, and it was merely a planet destroyer. So it follows that Star Destroyers can't destroy stars. For that matter, even if you parse it as equivalent to "star ship," i.e. a destroyer that travels among the stars, that doesn't work either, because a destroyer is a relatively small class of ship -- in
Wikipedia's words, "a fast and maneuverable warship of long-endurance intended to escort larger vessels in a fleet, convoy, or battle group and defend them against smaller, powerful, short-range attackers." But Star Destroyers are pretty much the biggest Imperial vessels -- except for Super Star Destroyers, which compounds the problem. And except for the Death Star, which I've just realized has its own nomenclatural problem, because it was called a space station, but it was capable of traveling under its own power, making it a ship rather than a station, because the defining characteristic of a station is that it is stationary, that it stays in one place -- well, one orbit, in the case of a space station. So that's no moon and it's not a space station either. It's a big round ship.)