In a public setting, I'll normally play dumb and juelez my way into a different topic or exit the interaction slowly if they prod into my relationship status so it doesn't seem like an actual rejection.
But the new tactic im seeing is a woman will come over and say "my friend thinks your attractive and wants to know if you're single" but won't tell me who the woman is right off the bat
In that case I'll tell them I'm already taken whether or not I actually am, because if she looked like Tinashe/Issa Rae she would have been confident enough to give me a choosing signal or at least move into my radius so I could take it from there.
This is bigger problem at the work office for me. I have to give them the obligatory 2-3 platonic Skype Business messages when they randomly message me before I fizzle out the conversation and avoid them as much as possible in the break room.