Also: this would never happen at a Dead show. First off, those balloons would be far too valuable at a Dead show to just waste throwing on the guitar player.
Second, if a Deadhead did rush the stage…wait: a Deadhead would never “rush” the stage. Accidentally stumble out on? Yes. Happen upon? Totally: a Deadhead could absolutely happen upon the stage. (“Hey, guys: look what I found!”)
Third, none of the three guitar-wielding members of the Dead would ever use their instruments as weapon, as each one of them cost as much as a Honda, but featured none of the reliability that Civics and Accords are known for.
Fourth, the Dead’s crew was a little more proactive than the Stones’, apparently. Parish would have given the guy a forearm shiver before he had hit the stairs.