The previous poster is correct. You can use your stroller up until you board the plane. It receives a tag at check-in that designates it for gate check. Yes, it is one of the first things unloaded but you might want to wait until everyone is off the plane before retrieving it at the door as it may take that long for it to arrive. Also if you are concerned about it getting dirty you might want to put it in a travel bag (you can get them at the check-in coiunter I believe, or purchase them at BRU).