This morning, someone used the term "handler," which I found amusing. Interestingly, "handler" might be a more fitting description than the phrase "skin in the game."
If counterfeit shares exist on a significant scale, which I believe to be a plausible situation. How would these shares be covered in practical terms? Would market makers (MMs) work to secure these shares for their counterparties discreetly, without triggering price movements that would raise regulatory concerns? Wouldn't it be crucial to prevent any volatile price action? This bid/ask activity you question NoMoDo remains unanswered.
I'm not even sure how you cover something that truly never existed. One might assume that covering could be achieved when diluted shares are added?
It's unlikely that any of us fully understands how such an issue would be resolved in a real-world scenario, particularly given that some question whether it occurs at all.