Over the past season I've worked with crews from different conferences who handle a certain mechanically differently. It covered it in pregame, but I still found it curious that there was not an agreement as to the mechanic.
Three Umpires. R1, R2 no outs. U3 in "C". Deep fly to center. R2 and R1 tag and go.
One crew has PU cover third...("I've got third if he tags") The other crew has U3 responsible for plays at third and/or second, PU staying home.