Who gets so embarassed by being seen in a toilet when they’re not actually doing anything?
Lord knows I’ve been taking a pee when a woman walks in to avoid a queue in the ladies’ dozens of times 
“Come here often?” is a good line for that scenario.
I think they’re blowing this a teeny bit out of proportion, perhaps to plug for some kind of compensation. I just feel that, from the information avaliable, the girl’s overreacting to a large degree.
But that’s maybe me. I don’t get embarassed by being walked in on in a public lavvy.