Deleting field collection via rules fails

I wrote a custom action that uses field_collection's delete function, and everything worked fine:

// Function hook_rules_action_info() not shown

function MODULE_action_delete_item($item) {
  $item->delete();
}

Here's your patch with the hook_rules_action_info() filled in. Ultimately, what this patch does is add a rules action "Delete field collection item" in the "Field Collection group"

If possible, I think it would be better to have everything just work when you select "Delete Entity". I wonder if it doesn't due to Field Collection's entity implementation, like something wonky in the delete function not properly extending the parent function.

This patch does work, but you'd have to know to look for this action when you might expect to just use the default delete entity. We may want consider putting this action into the "Entities" rule group, which would place "delete field collection item" right next to "delete entity", making it more obvious.

Here's rules' code for deleting entities. Not sure why the $wrapper->delete() doesn't use field collection's delete function.

/**
 * Action: Delete entities.
 */
function rules_action_entity_delete($wrapper, $settings, $state, $element) {
  try {
    $wrapper->delete();
  }
  catch (EntityMetadataWrapperException $e) {
    throw new RulesEvaluationException($e->getMessage(), array(), $element);
  }
}

The documentation mentions overriding the save/delete functions so that the entity api can pick up the changes, but I don't see what's going wrong:
https://drupal.org/node/878804

That's it. You can use the entity_save/delete/create() functions to manage your entity, or if you prefer, you can use the methods of your 'entity class', e.g. $entity->save().

To modify the default save/delete/create behavior, extend the provided controller class and override the methods accordingly. [UNCLEAR:]However, if you make use of an entity class you may also directly override the methods provided by your entity class, as the API functions entity_save() and entity_delete() pick that up.