BATTER BODY ARMOR
Michael Wolvertron raises a lone voice against a ban for body armor for batters. He says it will increase injuries.
This should be easy to check, since body armor is a relatively recent innovation. And it's the type of research Baseball Prospectus is good at. If arm injuries due to HBP have decreased in recent years (or the injuries per HBP, since HBP have been on the rise), then that presents a good safety case for body armor.
But Wolverton dosn't provide any evidence, even anecdotal. He just speculates that injuries would increase. I'm unconvinced.