Mutt,
Very true, but with a 9435 Kgs reduction in performance limited takeoff and landing weights, it shouldnt take long for the bean counters to notice that they are losing money!
Note this is T/O & Lndng wt only. It is quite rare to operate right up to limits for T/O & Lndng. With a large fleet you can schedule 747s to operate on less limiting routes where such limits never apply, so the actual cost of having a winglet missing is negligible.
Who notices one winglet is missing? Who will inspect both, who will see from the cabin if one is blanked off with tape? If it's presence bears absolutely no importance to the servicability of the aeroplane, and Airbus are short of spares or the aeroplane has no downtime scheduled, does anybody care apart from photographers in !!!!!!!!!!!!!!?