Why would anyone be surprised that they arrived together? Weren’t they both coming from the Upfronts? It would make sense to share a car. So much sense, in fact, that it would seem peculiar if they didn’t.

Yes, they were coming straight from the Upfronts. But them coming separately was one theory floating around to prove that The Webbies were only for the show and that outside of work, they couldn’t stand each other and couldn’t even spend 15 minutes in a car together. This theory is out of the frame now. 
There was also a theory to which I subscribed, that said David had surprised her and she didn’t know he was going to present for her awards. Sadly, this theory is also out of the frame now.