They must've just been on the ship spectating the P2, who was the star of the show. Like Stephen Hopkins said, he was getting some trophies to impress his friends. They had no reason to carry too many weapons, since it wasn't their hunt.
Maybe the lost hunters were inteligent enough to realise that there was no real point installing lazer systems.......I mean.....they didn't help any of the preds who bothered to fit them shoot straight lol.