From a user perspective, the 'How many people are you registering?' input, on the event registration form for multiple participants, is a required field. Therefore, it should have the red asterisk for continuity.
However, we can't just add the 'required' formRule to the element, because behind the scenes a '1' is a value of nothing (ie: no additional participants).
So what's the easiest way of adding the 'required' class to the element, without adding the form rule itself? It would be great to push this back to core, rather than us just overriding it in our CSS, even though it is a super-trivial improvement.