For reasons older than anyone reading this, baseball has enjoyed a special place in the hearts of judges and out of reach of many common rules of jurisprudence. We have extensive antitrust laws in this country, most of which don't apply to baseball. And if a fan is injured at a baseball game, unlike standard legal arguments of negligence and premises liability, we have "the baseball rule."
Like its antitrust exemption, the baseball rule exempts teams and Major League Baseball from injury lawsuits if a fan is hit with a ball or a bat. But with courts appearing more reluctant to kick injured fans out of court and the league advising teams to install more netting, the baseball rule might be close to breaking.