Ref,
If BU has a swing, you can bet your life the D is going to ask for an appeal. The pitch was called a ball. As far as the batter is concerned, there's no need to run to 1st base. He's entitled to know that the pitch is an uncaught 3rd strike and he has become a runner.
On the other hand, if the batter took off for 1st, the catcher is entitled to know if he should attempt to throw him out.
Both need this information right away. That is why BU comes up with the swing call if PU doesn't.
As far as your eloquent statement about refusing to open cans at the lower levels, don't you think you might be delivered a pre-opened can of something when the batter gets tagged out while still in the box?