For each user for whom the key existed:
No result is returned for users for whom the key did not exist.
Unlike most registry methods, the 8192 limit is not imposed because doing so would leave the system in an inconsistent state (some users would have the key deleted, others not), and in practice it is highly unlikely that any system would have that many users.
No output is returned for users for whom the key does not exist, i.e. only keys that were actually deleted are reported.
For consistency with other registry user methods, this would be better named as "RegistryDeleteUserKeys".