CSB & Ellen, guyz, thanks for your input.
Read my words carefully. In no way do I endorse or condemn any of the practices outlined.
In fact, I omitted several methods that providers have told me they use on a regular basis including texting, phoning, e-mail, SNAP, Twitter and other social media.
I was just telling the o.p. what methods some providers use.
Note, I failed to include the phrase "gut instinct," which does not refer to belly fat, btw.
And, most of the several ladies I know who "coffee," usually have a galpal or guypal sitting in the cafe observing. In some instances past, I have been an observer or, indeed, a participant, for that matter. In my case, mainly for "ginger" possibilities (my confessed personal weakness).
If the "gut feel" says no, just say you have an errand and/or lets make it happen manana. Or simply not engage at all.
The essence of meeting in a public space speaks for itself, imo, especially depending on appearance, spoken words and visible gestures. And, if possible, observation of the unkown person's arrival, companions and vehicle.