-
I don't believe there is such a rule. Moving line in a sprint is a legitimate tactic, it becomes controversial when you move line violently, or purposefully take someone into the barriers, as Groenewegen did.
Demare's move didn't impede anyone and was a gradual (or as gradual as you can do in a sprint at 60+ km/h) manoeuvre so I doubt the commissaires gave it anything more than a cursory review.
Is it just me, or did Démare go right from one side of the road to the other when he opened up his sprint? Whatever happened to the 'sprint in straight lines' rule reinforcement after the Groenewegen/Jacobsen incident?