Arguably, the main goal of Grid Computing is to facilitate the creation of Virtual Organizations (VOs); however, to date, not enough attention has been placed on the policies and mechanisms by which these VOs will operate. The core of the VO--roughly, the responsibility of each Physical Organization (PO) in the VO to contribute and not unjustly consume resources in achieving the overall goal of the VO--is at best service-level agreements (SLAs) that lack a concrete connection to the underlying Grid software and at worst an implicit "in-spirit" agreement. Unfulfilled expectations and obligations on the part of each PO can have dire consequences and can ultimately lead to the demise of the VO itself. This paper identifies three general policies regarding resource utilization by which VOs might operate and presents the ramifications of each policy on the VO's day-to-day operations and the VO's ability to actually enforce the policy. A prototype implementation of a VO with the "you-get-what-you-give" policy is the basis of a concrete cost/benefit analysis of policy enforcement for this type of VO.