This is always a difficult question to answer.
(Yes, I've been asked this many times)
I call it a "situational" balk.
For the coaches it always depends on who you're coaching. If your player is the pitcher you belive it was a cheap balk call as in..."Hey ump, he was just trying to put the batter on first base, no deception or anything like that."
If your player is standing on third base you believe it was the proper call to make as in... "Hey ump, that's a violation of the pitching rules and a balk should be called."
This, to me, is one of those discussions (and there are many) that falls under the category of... The Rules vs It just ain't Baseball.
This same scenario actually happened in an NCAA, Div I regional game last year. The ump called the balk and the winning run scored.
I can only say this:
Will the ump have to apologize for making that call? NEVER! (because by rule it was correct)
Will the ump be criticized for making it? FOREVER! (because, to many, it just ain't baseball)