Throwing to an unoccupied base!

[Don Mueller]

Originally Posted by PeteBooth

You have not seen it because it is a very difficult move.

In addition to what others have said, the aforementioned move MUST be done in ONE continuous motion. The problem with this type of move is that inexperienced F1's have a tendency to "hang" their free foot as to freeze the runners and then throw home or pick them off. In other words a "break" in their motion as opposed to ONE Continuous motion.

Pete Booth

There may be many reasons you haven't seen it, but difficulty of move is rather low on the list, IMO.
It's the same exact move lefties make to first and the only difficulty they have is self imposed when they try to get too cute.