Actually come to think of it, I think my $25 offer is for third world countries where the alternative is an unusable disgusting toilet. I think my price is inversely proportional to the condition of the free toilets. Countries where bathrooms are so bad, you would need to get a fairly expensive hotel to get even a decent toilet. In such cases, I would rather pay as much as 25 to use it. I know I am one of the very few who has such an extreme phobia of dirty commodes.
Never would pay to pee, of course.
Hell, some bathrooms are so bad, I might even consider a nature dump in the wild compared to using one of those bathrooms.
As far as the revenue factor, you know what, the more I think of it, hmm, not such a great idea anyway in the flight. To avoid the loss of more than a seat or two, you would also need to replace one of the free bathrooms. Probably better off paying a bonus to a FA who takes on the "toilet cleaning" duties in the international flight.
Regarding the fact that women can be nastier than men in using public bathrooms to vent their frustrations, I did read in a film projectionist blog how the women's bathrooms can be the nastiest where women intentionally spray stuff onto the wall. We do have some sick people. It's a pity that some passengers dont feel any shame when they exit a bathroom and the next passenger will get to see what a mess they made.
I thought maybe an educational film on the video monitors would be useful to third world based travelers. But then, that would be too funny to implement.
I think everyone uses public toilets as a kind of last resort only .
Oh, there is a last resort and really really last resort. An public bathroom would be for me to relieve myself so I won't be uncomfortable for the next few hours. An airplane bathroom use would be where I wouldnt want to squirming in my seat unable to concentrate on a single other thing for the next few hours.