...or, Michael would put on the hat as he was leaving. Since no one would have paid much attention to him before the shooting, they'd look up--and see a guy with a hat. That'd add to the variables that witnesses might offer the cops. Clem had a good idea.

BTW: when Gotti had Castellano whacked, all six gunmen dressed in identical hats and coats, and used identical weapons. That made it next-to-impossible for witnesses to positively identify any individual. None of them was ever indicted for that murder.