Nice thing about barriers is they work both ways. If somebody is behind a barrier it is difficult for them to harm me. If they can stick a gun through a port I can stick a bullet through it etc.

First time I went into a police station and sa they had installed some nice new heavy duty bulletproof glass I wondered what they would do if someone walked in and started forming plastic or taping a bunch of explosives to the glass. Couldn't hardly shoot at them. Just set there and watch them light the fuse? They could even watch the reactions.

Everyone always worries about guns. I have always thought high explosives were superior method of assault or defense.