If they are, a nice, quick smile, then let them respond and take it from there.  If they don't respond, just keep on walkin' and don't hold it against them.  If they are with someone -- especially if it's a woman -- don't even look.  Definitely don't smile.

for the most part, the best thing seems to be is act as if you are strangers.  While they might be alone in a store, you never really know for sure.  If you pass him/her on the street and are pretty sure the other is alone, a small smile and a nod might suffice.  After all, they don't know if you are really alone either.

Swim

Like Dionne Warwick sang "Walk On By" ( or Isaac Hayes if you like his cover of the tune).

Most of the ladies I have discussed the issue with say just keep on walking.

I have seen one or two in public ( Starbuck's or the like ) We recognized each other but kept it to ourselves.

He/She may appear to be alone but you never know.

I might give a regular hey how you doing smile like I give to complete strangers to a client and expect the same nothing more. DO NOT WALK UP ON ME, DO NOT TALK TO ME ETC, doesn't matter if i'm alone or not. I don't want a client walking up on me, if we're not out on a public date please act like you don't know me until we make an appt. Believe it or not nothing personal. I've heard far too many horror stories of guys following the provider around etc

that won't arouse suspicion but will let the other person know that they are remembered.

I suggest rubbing your ear lobe between your thumb and index finger.

I would never acknowledge another provider or gent outside unless they made it obvious it was ok to do so or unless the discussion has been had previously and i could clearly see they were alone and i knew they're real name (which i usually do with regulars and the select few providers that i am closer too) but it has been known for me to pass somebody and then they'll sms to say they just passed me and it was nice to see me even though they or I couldn't speak at the time but it very rarely happens that I've personally bumped into people from this world... but when it does colide its all about tact and caution as you wouldn't want to embarass somebody or make them go a horrendous colour of red in public. Also you would expect the same caution and respect if somebody saw you in the street or generally out and about as everybody on this site (no matter what capacity they are here) first and foremost have a life that they live outside of this.

Hugs Casey xx

You do not and can not know who might be with the other party...  or even aquaintances who are not with them but might observe.
The correct way to handle this is to continue about your business without diverting into their path nor away from them.  If you happen to pass you can make light eye contact, a smile & a nod as you would while passing any amiable stranger.   You can have a laugh about it behind closed doors.

Just walk on bye with no acknowledgement.  There are too many things that can go wrong, too many other people who may be within sight.

Only if you have reached a level of significant real friendship should you even THINK about anything else.  If you do not know her real name, met her kids, walked her dog with her, etc., then ignore her.

You can always drop her an e-mail later and talk about it.

I HAVE bumped into strippers that I knew from the clubs in public, though.  My suggestion is that it should be the ladies preference in how to respond.  My personal inclination would be to maintain a low profile, let you take the lead, and maybe send you an e-mail afterward.

it depends on the kind of relationship you have with them. I know two by real name and they know mine; we say hi and just shoot the breeze if we see each other. We don't hang out, though, as our civie lives are different.

Otherwise, pass them by, too.