That wouldn't stop an advanced player from rushing. You can use a wild-goose to get through a pirate base unscathed. Send in a scout first and have it run across the gravity well. All the pirates will follow it. Your fleet follows shortly afterwards, and while the pirates are distracted chasing the swift scout, you rush through the gravity well to the other side. If you do it right, you get through the pirate base and your scout just has a few scratches to show for it. It does take planning and prep, though, and you'll be cut off from reinforcements (which is pretty major this early in the game). Still, won't prevent a rush outright.
If anything, it's a little more dangerous because a player won't be anticipating such a brazen move from his opponent.
