[Grim Tuesday]

There is no rule that says you can't use your bumpers to your advantage. If you want to use them to get on top of the barrier, you can. Of course, anything used to damage the field is illegal, so don't use them for that. If they try to tech foul you for 'gaining advantage' from your bumpers, ask them under what rule they are giving it to you under. If they have any doubt in the legality of the bumpers, they should make you comply, not modify the rules to allow potentially illegal bumpers.