The point of this party (if you read the small print in the image) is to have a fun charity event strictly before the conference starts. It is explicitly outside the timeline of the "tech event."
if they are developers, they would not go to a tech event dressed like that.
You seem to be ignoring the fact that they did exactly that.
You might want to google "playboy bunny outfit images" because I don't think you know how much less material there is in one of those than in what the women are wearing in the Techweek invite. The Techweek invite images actually show very little skin.
