Can checked swing be a 'fourth out' appeal?

[Rich]

Originally Posted by Chukinrox

The question is ... if the plate umpire rules it a ball or couldn't see it because the catcher blocked him out, and the catcher made a throw to second because he didn't hear the ump call a strike, can he now appeal to the base umpire about whether the batter swung or not? We all know that 95% of the time you cannot tell whether a batter swung while in the B position but would this be a proper appeal or not is the question?

We DON'T all know this.

I can call a check swing just as well from B or C as I can from A or D. Saying otherwise just perpetuates this myth.