This is a pretty crazy practice drill that Vijay Singh uses quite often on the practice range. Vijay uses this swing aid to point out flaws in his swing at impact. He typically likes to work a fade, so he puts the umbrella slightly right of the target line. The umbrella forces Vijay to start the ball just left or straight down the target line, and, it keeps him from pushing the ball.
Thank you to the Crowne Plaza Invitational for uploading this video!