Does she carry a glucogon shot with her?
My daughter never goes anywhere without hers, and all family and teachers have been trained to use it if they ever find her passed out. It's a massive dose of sugar that will instantly shoot her blood sugars to the roof if she ever goes hypoglycemic to the point of losing consciousness.
To the question of counteracting a full dose of the pump's entire reservoir, I don't know if the amounts of glucogon in the shot would be sufficient, but we've been told it's a pretty massive dose for emergency situations. As in "If you find her unconscious, give her this shot 1st, call 911 2nd."
Also, the new T-slim pump uses a new system where insulin is relayed from a main reservoir to a tiny holding area from where insulin is actually pumped down the tube to the port. In theory, the person in never directly exposed to the full reservoir.