I heard this story many years ago. I don't know if it's true, but I when I related it to Roger Bischoff (translator & compiler of The Way to Ultimate Calm: Selected Discourses of Webu Sayadaw), he said it sounded like the kind of thing the Sayadaw would say.
The son of a meditation teacher had heard that 's feet didn't touch the ground when he walked. So one rainy day, he crouched down with his head close to the ground, so he could watch the Sayadaw's feet. The Sayadaw walked over a wet area, and when he reached a dry area, the young man noticed that his feet left no wet footprints. "Sir," he asked, "are you walking or flying?" The Sayadaw stopped and replied, "If you pay as much attention to this spot [between the nose and the upper lip] as you did to my feet just now, perhaps some good may come of it."