Let the cabin write one of its own rules. People defend the rules they helped make.

A rule handed down from above gets tested, and a rule people wrote themselves gets defended by the people who wrote it. Giving away one real decision costs less control than it appears to, because you keep the ones that matter and gain a group that polices itself. Ownership is doing the work there, not the rule.

Hand your group one genuine rule to make this week, and accept what they come up with within reason. Say beforehand which parts are not up for grabs. Then let them enforce it before you step in.