my understanding is, that if the boat hails for room at a mark or obstruction, regardless of entitlement you must give it to them, you can not push them the wrong side of the mark, even if it doesn't cause a collision.
Yes it is; however I would be trying much harder if damage might result. You would have a stronger case for proving the barging if you can say "he came in so late I could not give him room fast enough, this is the only reason (s)he hit the (nice soft inflatable) mark...."
