What they are doing...
I am sure that if they are hatching as they pull out the trays the hatchery will let them continue and still ship them out. BUT, if they hatch too late, they are hatching in the waste pile. Where they put the unhatched eggs and dead chicks that are going to be used for some sort of chicken meal for animal feed.
If they hatch early, they will be fine, as long as they get to their destination quickly.
They do not help chicks to hatch (a chick will sometimes be stuck in the shell and some hobbyists will peel the shell to help the chick to hatch,) as this is too labor intensive, and a waste of their time and money. Other than providing the correct temperatures and humidity so that they chick should hatch, they do nothing. After the chicks have hatched on their own, they then sort/sex/ship.
I hope this answers your question.