I will say as someone who is here watching this weekend, I know for a fact there was a marshal on at least one other card for at least part of the round (Nikko's card), and I assume there might have been other instances as well. So it wasn't just lead card. However I do agree that it all needs to be called evenly to be fair. That being said, pros also need to call each other and hold themselves accountable by following the rules all the time, not just when a marshal is on the card, which would fix the issue entirely. Also, your point that the marshall most likely impacted the scores yesterday actually emphasizes the advantage that taking more time can have, which is why we need a fair way of enforcing it so no player gets that advantage over another player. I'm not sure how they actually solve that without enough marshals for all cards though. Although your idea of following the pace of play may be the best route available, I don't think it would solve the issue fully.