I really don't think it's prudish to think having sex in a public toilet is unacceptable. It could also result in you facing some legal problems as well.
All things considered, the toilet can often end up being a pretty grotty place as well, which can't possibly add to the ambience. And of course the impact on passengers that may wish to use the loo for more conventional purposes...if you're in and out of there quickly then no-one is going to have a good time anyway.
Plenty of opportunity for nature's desires in IBZ, so I am told.
