Orange Scarf Guy—or Waldo, as I call him—could be an Equalist.
Notice how he’s hanging out in the upper-right corner of the audience. Merely a couple minutes before the equalist attack, we see one last flash of the fans, and…
It’s not surprising, really, seeing that he was at the rally. It’s more of an observation.
Waldo is Amon, you guys
Also, the above screenshots are where he appears in the episode; we found Waldo!
I doubt that’s Waldo. It doesn’t look very much like how he’s appeared in the past episodes.