When the defense is bunched to stop a run over the middle, it's a safe bet that the defender chasing a receiver to the corner won't have help over the top.
All teams do it. It's not always succesful because it depends on good timing and good effort by a receiver with good strength or jumping ability.
When it fails, everyone boos.
Since this is on CB, I'll also write that it's imperative that the QB puts the ball where only the receiver has a chance to get it.