Shouldn't delete_entities() delete all related records?

Just curious, why doesn't this function delete each entity's associated subtypes and metadata?

http://reference.elgg.org/entities_8php.html#b1cec89ed4e555dfe915eb45cb450c08

I see all the orphoned records in my DB after deleting entities.

Specifically, I see data in this table that was related to the entities which were deleted.  It's as if a foreign key relationship was broken.

  • elggmetastrings

I do find it odd though that this page says the opposite should be true,

http://docs.elgg.org/wiki/Engine/DataModel/Entities

If you delete an ElggEntity, whether it be a site, user, object or group all its metadata and annotations will be automatically deleted.

Does anyone know what I may be doing wrong?  I'm on v.1.5.