The nice thing about barricades are that they protect large groups that may not have planned for the events.
But somebody needs to plan for those and arrange the logistics. Then, they end up being useless when LEO moves you elsewhere, and you probably lose them at the end of the day. I can stick a LOT of earplugs in my med-kit and hand them out when I see an LRAD..
I think that we're discussing different things, as these aren't pressing concerns when building barricades.
earplugs do literally nothing
From personal experience I can say that well-fitting earplugs did bring a significant reduction in pain-level.
That is ofcourse a very limited and subjective observation, however: sound is sound, the laws of physics still hold.