Oh yes, turned one politely away last month (well she wanted on my wait list, I put her at the very bottom).
She wanted me to hold the spot for over a month. She wanted a special diet. She wanted open to close.
She then asked me what would happen if she picked up late, then gave me a couple of reason why she would possibly pick up late. Questioned vacations and days off.
The kicker was she called one of my current client references and actually told her she would be keeping track of all my time off.
I told her I would get back to her in a couple of weeks after finishing up with my scheduled interviews (wanted her to understand it was my decision). Then I admit I completely forgot about her because she was a BIG NO, until she called back after a few weeks. That's when I told her I had filled the spot and put her on that wait list going nowhere.
The happy ending is I found a perfect family/fit at the very next interview.