If you can do a 46 on such a map, then you sure know also that you can end a map by crushing into the ceiling. Seriously everyone who played 2-3 TTRR's knows this is a valid way to finish a map. Don't have to be "oldschool" to know.
In each league are different rules, Here such I was looking and did not find...
You're right that it is not written in the rules. But imagine how big the rule book would have to be if every eventuality would have to be listed there.
And noone would bother reading it either. Therefor the guideline for one should be, if it's allowed in funners, then it's allowed in league games also. Especially in TTRR, as it is played in funners as in league games...
Btw, talking of this, i never liked when peopl touch the finish on the side only. Imo one does have to finish
on the finish, or touch the wall behind it. Touching the side feels like cheat really.