When my mother and I went out for the day when she was older we used to travel between the various loos, stopping at most of them "even if neither of us really needed to".
I lived in Bath then, and most of the old public WCs had been closed or had restricted opening hours. Those in shops were few and far between, with the result that the Ladies in Marks and Spencer usually had a long queue though there were quite a few cubicles inside.
It's fine if you go to a shopping mall, but even the large department stores have very limited facilities now. Locally we just have Morrisons, with three cubicles shared between the sexes - and usually at least one is out of order.