As someone else has said, it's an 'oddly liberating' experience to walk away on seeing the WG. Happened to me recently, my first time. The AW profile claimed she was 5' 11'' and size 14. Actually, she was, in my estimation, about 5' 4'' and a size 16. Ugly, too.
Told her she was 'not what I'm looking for' and left. Phoned a regular a couple of streets away, a Brazilian, size 8 and gorgeous, who was available.
Both meetings that morning were memorable, but in different ways!