Yep this has happened 3 times to me, all within the space of 100 yards all on seperate occasions.
1.
I was sat in Greggs in Wolverhampton eating a chicken bake and Erica who used to work for Sasha's in Walsall came across and said "Hello Greg are you still into (then she mentions my fetish)", I nearly fucking dropped dead of embarrassment, there was a table either side of me with people sat. Not sure if they heard or not. She pulls a pen out of her bag and scribbles her number on the edge of the chicken bake bag and says "Call me". Most embarrassing time ever.
2.
Greggs again, this time I am enjoying a coffee and am sat at the last table near the entrance, I can see up and down the Wulfrun centre and am looking and I spy Lisa the maid that used to work for Sasha coming towards me. She smiles, I smile, she stops and has a quick 'How are you' chat. Nothing uncomfortable or embarrassing mentioned, quite a pleasant brief chat.
3.
Iceland, 100 yards up from Greggs in the Wulfrun centre. Frozen chip freezer, a lady was in my way, I asked her politely to move up so I could open the freezer, she turned around and it was a local working girl that I used to visit on occasions, she was with her fella, we never said anything to each other.
Those are my 3 encounters with a working girl in public.