It's likely it won't have much effect on those already botted. Their uplines will come out with the usual spiel about the documentary being biased and total bullshit while showing off their houses and cars.
What is more likely is that those who are considering signing up or those who are about to be targeted may be able to say no.
Someone will see it and say "Hey Karen, I just saw a programme about that mlm you were thinking of joining". Or something to someone about a programme on MLM's.
For those on someone's list to contact to push the opportunity they will have the knowledge that it's not going to work out.
If it's been done right it's possible it could stop thousands signing up to MLM's. I'm guessing everyone here will be sharing it on social media, as will plenty of others.
People posting it on bots timelines will happen as well.
The BBC is one of the most trusted broadcasters, so hopefully that will help it be taken more seriously.
Hopefully the newspapers will take up the story as well, people sharing that on social media will help as well.
Maybe I'm being too optimistic but I do fully believe this documentary has the potential to save a lot of people from joining.