First, a short clip of the Rolling Stones from a 1981 concert in Hampton, VA (download video, 2.7 meg MPEG file) in which Keith Richards, perhaps feeling a bit spry after a pre-concert blood change, takes a couple of swings at an overly excited fan who jumped onstage. (video found on Metafilter)
Next, a couple of ads with (simulated) onstage accidents featuring the group Harvest (Stumpy Pepys and Sammi Curr are nowhere to be seen), all in the service of persuading the viewer to plunk down the money for a virtual guitar rig called Guitar Rig. These spots get extra credit for the slightly addled English tagline, "Don't dice with death". (link found at Create Digital Music)
If you need further persuasion for staying off the stage, just have a listen to Brian's Shut Up and Play compilation. A healthy dose of what the so-called professionals sound like live in concert should keep you from picking up your guitar ever again.