[Tim C]

Gordon:

There is no such thing as "one man mechanics" . . .

Respectfully, I also have never seen or even heard of the BU getting trapped as you have listed.

Now we did, long ago, do the mirror thingy that if the BU felt pressure and went foul that the PU would cover inside (i.e. mirroring)and lead the play to second base if necessary.

I agree with Rich's statement in basic terms . . . the PU following up the line has many, many more things more important than helping on a swipe tag or pulled foot. (Actually a pulled foot would not even make my radar as a PU).