Originally Posted by
corporate-wage-slave
I say this is in the 1% area. It may be 2%, it may be 0.2%, but it's not 20% of flights affected, to answer the question - so no. I suspect you are referring to hand washing, the lavatories themselves are more gravity-suction based than flush toilets. Usually they put some bottles of Harrogate water in the toilers if this happens.
Personally I wouldn't want to sit on a toilet where someone had done their business and it was still there. The toilet couldn't flush due to no water.