If he was hiring sober companions to play with.... The confidentiality clause would stop them from warning each other about Holmes, and if he's truly horrible he might pay them off big time at the end with an impressive bonus.
Long term observational subjects?
Remember the Sound of Music where they're explaining to Julie Andrews what happened to the 11 Governesses before they solved a problem like Maria?
What if he owns the Sober Companion Company which would mean that he really, really choses and vets who they send him to make sure that he has a good time?