The reader will only be able to understand the purpose and meaning of this annotation and its relationship to the Natural Social Contract (NSC), if s/he has first read the Introduction section of the NSC and its explanatory and elucidating annotation.
1) These are the general Stipulations concerning the Property Entitlements and Responsibilities that any Freeman-A has with respect to any Property by which Freeman-A Decides whether s/he has been Violated by another Freeman-B and also by which any Freeman-B can Decide if Freeman-A's use of hir (Freeman-A's) Property has Violated Freeman-B or has Breached the NSC. They are Symmetrical Stipulations because they apply equally to all Freemen and each could be in any of the positions with respect to the situations involved.
2) In practical terms, Possession is very close to Ownership. This is particularly important for both parties to realize when some Object is rented or borrowed, because such a transfer of Possession and Control makes the new Possessor (the renter or borrower) fully Responsible for all Harm which would come to any Freeman by way of that Object. This is because the new Possessor of the Object would be the last Controller of the Object that caused any such Harm and thus would be the Effective Cause of the Harm. For this reason it would be redundant (and could lead to ambiguity) to have any additional Requirement for Adequate Control. However, if the lack of Adequate Control were actually an Effect of some prior Action of the Owner (or even a previous Owner), then it would be up to the new Possessor (the renter, borrower or new Owner) to in turn seek Restitution from the Owner (or Previous Owner) for Breaching the rental, borrowing or transfer of Ownership Contract (if such an eventuality is in the Contract). This latter is the reason why clear rental, Ownership and even borrowing transfer Contracts specifying who is Responsible for what are so very important. This prime Responsibility of the last Freeman to Act upon an Object is also a reason why any sensible Freeman will not wish to take Possession of an Object about which s/he does not have sufficient knowledge or skill to exercise Adequate Control.
3) Stipulation B.3.a describes the "strength" of the Property Entitlement of the Owner or Possessor of an Object or Parcel of Real Estate. This Property Entitlement is as strong as one's Self Ownership of one's own body - the absolute Liberty to do whatever is necessary to remove all Material Existents within its boundaries (if not the actual Freedom to do so). There is only one exception and one restriction to this absolute Liberty both of which are Stipulations of the NSC. The exception (within Stipulation B.3.a) is when Freeman-A is hirself the Effective Cause of an Object, of which another Freeman-B is the Entitled Owner or Possessor, being within the boundaries of Freeman-A's Property or Possessions. And the restriction (within Stipulation A.6) is when Freeman-A has given prior Permission to another Freeman-B for the Object to be there and now is Withdrawing that Permission, in which case it is Required that Freeman-A Must allow Freeman-B to remove it in such a manner that no Violation to anyone occurs (as is explained in the General Stipulations Annotation). Except for these two situations, Possession is such a strong Entitlement, that a Freeman Must always accede to another's Possession Entitlement and, if a Valid Contract has been Breached, afterwards act to gain Restitution. The situation where Freeman-A is the Effective Cause of an Object, of which another Freeman-B is the Entitled Owner or Possessor, being within the boundaries of Freeman-A's Property or Possessions, is either Permitted transfer (perhaps physically by an Agent) or Theft (or kidnapping), and is thus different in nature from when some third Freeman-C is the Effective Cause of it being there. Except when specified differently by a Valid Contract, the Freeman who was the Effective Cause of the transfer is always Responsible for its return to the Entitled Owner or Possessor. Under the situation of Theft (by the current Possessor), the Freeman Owner of the Object may remove it, or not, as s/he wishes because s/he has been Violated by the Owner or Possessor within whose boundaries it is located. In the case of kidnapping (a combination of both Responsible Harm and Defendable Threat), the kidnapped Freeman always has the Entitlement to escape if s/he can.
4) Stipulation B.3.b clearly states that a Freeman-A is Entitled to RePossess any of hir Property that was Stolen, from any Possessions or Property (even the Person) of the Thief or of a Freeman-B who Permitted the transfer of the Stolen Property onto hir own Property. RePossession of such Property can only be accomplished by Actions that are the Effective Cause of no more than Necessary Harm and all the considerations and remarks applying to the concept of Necessary Harm that are discussed in the Dispute Resolution Annotation also apply here. However, with regard to a Freeman-A's Property being within the Possessions of any Freeman-B who was not the Effective Cause of it being there either by direct Action or by simple Permission, there is no such Entitlement. To the extent that a Freeman-B has not Violated a Freeman-A, then Freeman-B retains hir full Property Entitlements and Liberty. An Object which is thus within the Possessions of Freeman-B who had neither brought it there nor given Permission for it to be there is in a State where Freeman-B has Possession but not Entitled Possession (unless it was Abandoned by its Owner, in which case s/he does have Entitled Possession). In such a case, even though Freeman-A has Property Entitlement to the Object, s/he has no RePossession Entitlement. I see no resolution to this "limbo" status as long as the Object remains within the boundaries of Possessions over which Freeman-B has full Entitlement. The only resolution will come about if Freeman-B attempts to move the Object through adjoining Egress Real Estate the usage Contract of which does not allow the transport of Objects without Possession Entitlement. At that point it can be confiscated by the Egress Real Estate Owner and returned to Freeman-A for the costs of that Action.