Your original cataloging
There are two areas where it becomes important to identify "your records." The first is in section B.3 where "WorldCat record" is defined. In the final paragraph (top of p.2) it states:
An OCLC Member or Non-OCLC Member may Use or Transfer the following without complying with this policy: (i) a WorldCat Record designated in WorldCat as the Original Cataloging of the OCLC Member or Non-OCLC member...In other words, your own original cataloging is not covered by this policy. That's good news, but the practical application of this may not be simple. The way to determine this is by reading the MARC 040 $a subfield, presuming that the system you used at the time set this correctly. There is also the fact that OCLC merges duplicate records, so two instances of original cataloging could become one in OCLC...
Then there's the issue of how this affects down-stream users. For example, if Library A gives a copy of all of its original cataloging to Library B, and says: "no restraints on use," is Library B still held to the policy in terms of its use of WorldCat Records? According to the policy (E.5):
Regardless of the source from which WorldCat Records are received, Use and Transfer of WorldCat Records is authorized solely by OCLC pursuant to this Policy.This seems to contradict the "your original cataloging is not covered" clause, although perhaps contract law deals with these kinds of apparent conflicts in some neat way. I would say that your original cataloging is not considered a WorldCat Record (as defined in the policy) except that the language of the exception refers to the original cataloging records as WorldCat records.
Also not clear is how this relates to the request to include the OCLC policy field in exported records. Although it isn't stated here, it would seem that original cataloging records should not contain the statement. (Those records could, however, be given a CC license by the originating library.)
Another key area relating to a library's own records is section D on the transfer of WorldCat Records. Section D.1.a states that libraries can transfer WorldCat records of their own holdings to other Members and Non-Members. Holdings is defined in the glossary as the OCLC institutional symbol on the record.
Section D.3 gives the logical converse of that: that to transfer WorldCat records that aren't of your own holdings, you must obtain permission from OCLC. This places restrictions on any institution that has received records from others, and could have implications for union and consortial catalogs. There isn't any mention of consortial agreements in the policy, yet many libraries already share their records in one or more such databases.
Even if we work out the conceptual issues, both of these pose some real challenges in implementation since our bibliographic data today often does not clearly define the origin nor the source of the record, especially data that is not transmitted in MARC format. I'm really not at all sure that we could actually do what the policy requires.