Programmatically disable product (via price set)

I am trying to programatically disable a product via a price rule. The price comes from a webservice and sets it fine. However if there is no price returned i wish to disable the item.

Approach #1:
In my rule I can safely and cleanly call

$line_item_wrapper->commerce_unit_price->data = commerce_price_component_delete(
          $line_item_wrapper->commerce_unit_price->value(),
          'base_price'
  );
  $line_item_wrapper->commerce_unit_price->amount = NULL;

This removes the price from displaying on the item, but still leaves the "Add to cart" button, and i believe so because of this line here
file: commerce_cart.module:1905

    // Do not allow products without a price to be purchased.
    if (is_null(commerce_product_calculate_sell_price($form_state['default_product']))) {
      $form['submit'] = array(
        '#type' => 'submit',
        '#value' => t('Product not available'),
        ...

Approach #2:

$line_item->commerce_unit_price[LANGUAGE_NONE][0]['data']['components'] = array();
// Clear price, disables item if no price is found
unset($line_item->commerce_unit_price[LANGUAGE_NONE][0]);

This way i am able to get the "Product not available" text appearing over the "add to cart" button, however i receive
Notice: Undefined index: amount in commerce_price_field_formatter_view() (line 442 of .../modules/contrib/commerce/modules/price/commerce_price.module).

Approach #3:
If I attempt to disable the product instance by programmatically setting it's 'status' to 0 nothing happens,

  $line_item_wrapper = entity_metadata_wrapper('commerce_line_item', $line_item);
  $product = commerce_product_load($line_item_wrapper->commerce_product->product_id->value());
  $product_wrapper = entity_metadata_wrapper('commerce_product', $product);
  $product_wrapper->status = 0; //disable

this is because the code that checks this calls the database and checks the status field there, and not one set in a loaded instance of the product.

file:commerce_cart.module:1479
$products = commerce_product_load_multiple($product_ids, array('status' => 1));

Can there be some formal way through code to possibly allow what I am doing, or is there another way?