For a long time early in my Air Force career I was an instructor pilot in UPT (undergraduate pilot training), and although it was rare, students occasionally attempted gear-up landings. Sometimes they succeeded.
There was one famous story about a solo T-37 student who landed with no gear. As he turned final, the controller repeatedly warned him about not having the gear down, but he pressed on and landed gear-up. He survived unscathed, and in the aftermath he was questioned about why he didn't respond to the repeated warnings to go around.
"Hell," he said, "I couldn't hear a thing with that damn warning horn going off."
There was a warning in the T-38 flight manual against landing gear-up in the event of a gear malfunction. Since parts of the bottom fuselage were made of magnesium there was considered to be a serious fire hazard, and it was recommended to eject rather that attempt a gear-up landing. However, as the years went by, a number of accidental gear-up landings occurred, none of which resulted in fire, so the warning was deleted as I recall.