Have a watch of this video.

To me it looks like the spectators have kicked snow over the hairpin corner.
Adds to the 'arse out entertainment' but wouldn't be on your notes and may not be seen in time to correct.

Notice how they cheer when the driver gets it right but fall very silent when they crash. Looks like a big drop over the edge.

And yes there are a couple of Stratos in there

How would you feel if you crashed your pride and joy on that corner?

Thoughts

https://www.youtube.com/watch?v=Ut9V1L8H8k4