Oh yeah, that is a great way to find out if someone is ticklish without actually tickling them.
Two quick ones, Saw a friend at the mall with her young daughter who had on a tank top that showed her belly button, I wiggled a finger in the air at the daughter to air tickle her, but her mom laughed just as much saying something like, "Oh, I can't stand to be tickled either"... Gave her the evil eye and a finger wiggle and she squealed "No!" I didn't take it any futher. Just fun memory.
Second, was at work. I talk with my hands quite a bit and I was talking about something work related and she got this smile on her face. I said, "What?", She said, "You have to stop moving your hands like that, it looks like you are tickling someone" 🙂