“Luckily, “vaccine status” doesn’t display itself prominently on our bodies.”
How do you know if someone is vaccinated? They’ll tell you. (Seriously. At the gas pump, in line at the grocery store and several times in elevators. It’s all I can do not to say, “I’m so sorry. I hope it works out for you.” Instead I just smile and offer a friendly nod.)
No matter what happens after that, no matter the response (if there even is one), I just say "Cheers!" and go about my business. Simple. Done and done.