A far-eastern based friend commented as follows:
There was shock and horror on the radio today about him thinking about charging passengers to use the toilets on his planes, it kind of amused me, I would love to see all those women who hog the toilets on long haul flights charged !!
I got caught once in a queue of about 10 of them, each one spent about 15 minutes in there, some returning wearing different clothes to when they went in. There should be a timer on the door so it springs open after a reasonable time....
Of course on the return flight from places like India and Bali the airlines could make a killing by charging due to the number of passengers with stomach complaints !