Those are GUYS hitting pro level shots. They cannot stop their 14+ oz rackets once they get them going, nor should they bother to.
Chrissie played with a lighter racket, a much more controlled swing, and also followed thru past the target most of the time.
The notion of following thru towards your target was to get duffer players to extend thru their shots, instead of stopping the swing at impact, like duffer's sometimes do.
In the old daze, the prevailing thought was if you followthru'ed wrapped around your body, you would not have time to recover towards center of intersect for the reply shot.
Now with TOPSPIN, the ball goes slower, you have more time to recover, and nobody is standing at net to volley away your passing shot.