I don't know. If I was preparing to ride at the Olympics, I don't think I would want to have to worry about the public during my warm up ride. NOT because I rollkur or anything nasty like that but because you just never know what the public is going to do......."ooh look at the pretty horsey...Can I pat him?"
If I remember correctly, the warmups started being closed to public viewing once rollkur was moving into the ring more heavily. The first one I remember was Las Vegas.
Btw, part of rollkur training is to force control of every step so that no bobbles can happen. So yes, many rk horses don't make the mistakes. BUT LOOK AT THE GAITS. Kittel's horse rope walks and trots! I've never seen a horse rope trot before but it was very apparent watching the vids of this olympics. Why is that not given 4 or lower for impure gait? Andalinde's horse was gaping, crossing his jaw and being held against the bit. Why isn't that lowering her score?
One question: what is the first rule of dressage? Horse reaching out to the bit. Look at Dujardin's victory lap. Her horse is hot hot hot but he can still reach out to the bit doing an extended trot, arching his neck and nose slightly infront of the vertical. Even with her riding one handed, he stays with her.
If we don't uphold the rules of our sport, we are just doing circus tricks.
Only the first trot up was closed to the public for the eventers. It was the day of the opening ceremony and they didn't want to divert the extra security needed to open Greenwhich Park to the public. I don't think it had anything to do with the security of the horses as they ran down the strip.
The trot up after xc the morning of stadium was open to the public, they just opened the gates early in the morning.
They close the dressage warmup (although the pink mesh fence is a new one for me-they couldn't look any more like they're trying to hide something if they tried) because rollkur is ugly and really looks bad to the public. The FEI officially allows it for a certain period of time and that time goes by awfully slowly if you're sitting and watching it.