[Angler]

ASA mechanics 3-ump system. When do base umpires walk the line? I've been given conflicting info from very good umpires:

a. Never with ANY runners on base (so 3U would NOT walk the line with a runner on 2nd, and 1U would NOT walk the line with runner on 3rd) OR

b. Only when there's not a runner at your base (so 3U WOULD walk the line with a runner on 2nd and U1 WOULD walk the line with a runner on 3rd only)

Thanks for your thoughts.