Here's the thing about celebrities—they can get paid for just about anything. Fifteen minutes at a party? That can cost a PR company or a brand a couple of thousand dollars. It's great to have Kanye or Sarah Jessica Parker roll through—it boosts your event's cachet and you give the peons present a chance to Instagram something worthwhile, like a blurry shot of Kanye dapping up Chace Crawford.
You won't exactly meet these people. No, they'll be surrounded by flashbulbs for the entirety of their brief stay, before they are corralled into an exclusive "V.I.P." area slightly larger than a thumbnail. That's where they'll spend the next 20 minutes (if that) in this godawful place, thumbing through dickpics on their iPhone or making idle talk with publicists.