[IamMatt]

Here I go again, looking to the book for an answer. Regarding balls and strikes, ASA says, "Every pitch is called a strike or a ball. Umpires don't remain silent when a pitch is ruled a ball."

It is a little less black-and-white with foul balls. Mostly the book discusses determining fair-or-foul on close ones down the foul lines; ASA says, "...on all foul balls, except a caught fly ball, the DEAD BALL signal is given." so I guess that says you should be signalling every foul ball, but not necessarily with the FOUL BALL signal, unless they mean that instruction to only refer to balls hit down the foul line. Glad it is so clear.

As a coach, I like decisive, consistent calls. If I don't hear a call or see a signal, I don't have to guess whether it is because I missed it, or if it was a "silent" call. We coaches aren't that smart, remember, and we need all the help we can get.