I never see a girl who is ill and would walk out halfway through if I thought it was bad. I remember a few years ago I saw a regular of mine and she had a cough when I arrived, and we got through the first round and her cough got worse. I told her I didn't want to catch her flu symptoms as she was blowing her nose as well. Her reaction was, "well you've been here an hour already so you would have probably caught it by now so there's no point leaving now."
I said no, I'm minimizing the risk by leaving and left. I only paid for half the booking as she should have been transparent beforehand that she had a cold and I would have rescheduled, so I was in my right. Anyway, it proves that a lot of these girls will put money ahead of the well-being of their clients. In fairness to her, she did text me a few days later to see if I was ok, which I appreciated, and was luckily fine.