Agreed but how often do you think people are checking in for family members, so they can get the benefits, while also staying elsewhere? Keeping in mind they are being treated at status at both places, its just nights and points that aren't posting.

And how does that added expense paid out for those family members compare to the lost revenue by someone making their side trips off brand.

While I understand the basis behind it, my guess is the rule is a net revenue loser for Marriott