Maybe she deserved it, being shallow and horny. But that doesn't speak to the morality of it at all.
if this girl wasn't at least into this guy, and wasn't getting any prospects messaging her, she could've gone looking actively herself and found the exact same guys in the area.
Furthermore, its not the lady that he was messing with. Its the guys that were on the wild-goose chase. He approached this woman in the normal manner.
I don't know, even if she knew, she might give him an A for effort.