I went to see it a couple of years ago, they had invited a load of riders, I seem to recall about 11 turned up.
Out of those a few took one look and bailed out before practice. Then some broke themselves in practice and gave up. Then on the morning it was wet and a few more bailed out.
Basically its very hard/tough and if you are in the middle of a season for a team that’s paying you, it could be in your contract that you don’t go and do something daft.
In real life it looked significantly harder than the WCDH course I was at in France a few years back.