He was, perhaps, lucky; though by default because of blood status Pansy considered Astoria one of her own close friends, the feeling was never returned by the latter. The timing of her invitation and Astoria's letters were simply coincidence. Pansy had seen Astoria and Draco's public communication but had dismissed it as him guiding the youth.
Luckily Pansy's vision did not give out and she soon caught sight of him. Trotting quickly to him -- ladies did not run, that was an act reserved for the middle and lower class who had no free time to spare -- she smiled broadly: "Draco! I almost didn't see you. How are you?" She barely extended her hand, hesitating; if he did not take it, she didn't want to appear the fool by holding it out.