How should I greet a nun or priest in public, without invading their privacy?

https://traffic.libsyn.com/anunslife/RNC-as236-dec-03-2021-nun-greetings-mx-shannon.mp3
Podcast Recorded:

A listener wonders, if she greets an unknown nun or priest in public, how to do so as a sign of respect vs. a possible invasion of privacy. Hear the full Ask Sister episode AS236 at aNunsLife.org. Hosts: Sister Maxine and Sister Shannon.

How should I greet a nun or priest in public, without invading their privacy?