I use a quart sized zip lock baggie with a toddler size diaper folded inside of it (inside out, with the absorbent part exposed). This takes care of the danger of the bag getting punctured, since the diaper soaks up the liquid (in a couple of minutes). Yes it's a bit of a distraction when using it, but I can choose when to use it, during a quiet part of the flight (cruise rather than thermal).

And I never throw it overboard - bad PR!