Would it not make sense here to also pass in the guid_column param for these? ie:

```php
$access = _elgg_get_access_where_sql(array('table_alias' => 'n_table', 'guid_column' => 'entity_guid'));
```

If you implement the new get_sql hook and attempt to add some addition logic that checks for a relationship on a guid (for example) you'll get a nasty DB exception because ```n_table.guid```  (```guid``` being the default param) doesn't exist.