I'm sure Stars is not going to police the home games as close as they might their own, but under the home games FAQ it does state:
I am concerned about collusion. What should I do?
Home Games Poker Clubs are intended for friends who know and trust each other. If you suspect improper playing tactics on the part of fellow club members, please email firstname.lastname@example.org
with details of the incident, and one of our game security specialists will review the matter.
Being paranoid doesn't make for fun games. If you have doubts, don't play or unjoin the club.