If you talk to one that’s not a SW, they won’t slap you. They will, smile, shake their head and nod in the direction of a SW. It’s no big deal.
The best is to make eye contact and if they walk towards you and initiate conversation, they are likely a SW.
Is it safe - relatively and depending on time of day.
I’m equally concerned about cleanliness. Depends on where and who. Some of them keep their stall very clean. Others not so.
That will work, eye contact and smile and take a step towards.