We have had this issue for a long time as well, and we tried many approaches to try to convince people to adhere. Alas, between the sheer number of Policies in place (partially because we are a large company) and some Lead Links simply not caring if a Circle Member adheres to a rule that doesn't affect their Circle, there was little enforcement on any Policies.
So, what we've since done is to start adding consequences into the Policy that gives whoever is most affected by it the authority to enforce it. For example, if our Finance department is having Tensions with people not reporting their spending, they can propose a Policy at the GCC that says something like:
"If company money is spent, an expense report must be filed within one month. If this Policy is violated, @Finance has the authority to adjust that Circle's budget accordingly and/or hold the violating Circle Member accountable in the same way(s) as their own Lead Link could."
Hopefully that helps!