Running up the course without a bicycle.
I had always thought it was a DQ - just spent the afternoon looking through UCI fines and penalties and it is not there.
Pushing is, drafting cars is, violent conduct is, riding in car is .... But nothing I can find about advancing without bike.
I certainly don't know all the rules although I have read them a couple times, but I'm not sure now that is one. Which is why I would not DQ anyone for a rule that was not written.