No wait! if you look closely in the video you can see he turns around when he tosses the can into lawnmower blade spinning 3,000 RPM which shreds the can into sharp flying shrapnel. It's 100% safe, trust me. When me and my buddies were kids we did this all the time for a science project.
I thought everybody was down on the flying lawnmower guys, which I thought was cool. Then I looked at the video in the original post and see why . . . I agree. Their last name must be Moon.