I have a doubt here. While I agree that the passenger cannot occupy the reserved seat without the TTE's permission until the designated Boarding Point, I dont see anything in this rule that says the passenger is not entitled to board the UR compartment of the train without buying another ticket. After all, the passenger has paid the full fare and should be entitled to travel in the train even if not in the reserved coaches. This is just my doubt, and I might be wrong, but if there is any official clarification on the same anywhere else, it would be useful to see.