Comment by zeumo

Dust can also be an issue. It's definitely a cause of concern for pistachios, where cracking the shells releases enough pistachio dust to cause skin rash to my allergic daughter, even though she's never touched a pistachio in her life. Cracking shelled peanuts can likely cause the same issue, I'd wager.

Although peanuts served in planes are not in the shell, I can imagine how having potentially allergic people in close contact to people potentially oblivious to allergy issues eating peanuts sitting right next to them and eating peanuts could be problematic.