I guess the Society has to figure out whether they lose more by the drip drip drip of inactive ones being shunned and the depressed climate it may create at the Kingdom Halls versus the negative effect associating with an inactive one has on the faithful and the number who would reactivate themselves to save their relationships with family and friends.
Imho there would be an intial house cleaning - large numbers announced or unofficially announced that would shock the congregations. This shock would cause the faithful to run around preaching and teaching like never before. They'd do it because for sure the end is coming. A well placed WT article or two discussing Jehovah cleaning his temple would suffice.
After the initial spurt of house cleaning , things would settle down. The WTS would be left with a stronger core from which they could replace those who were inactive with stronger members and they wouldn't have the bad influence of the inactive ones in the congregation.
They wouldn't have to announce anything publicly. A couple of WT articles or talks that discuss the pitfalls and dangers of associating or being friends with someone who is inactive would suffice to isolate the inactive.
Those who are considering fading or currently fading would slow their fade down and possibly stop the fade in order to maintain relationships. The WTS DOES NOT CARE WHY YOU PREACH AND CONTRIBUTE - JUST THAT YOU DO IT.
I expect we'll hear more about this within 6 months. Which means the articles are already written and laid out.