API should throw error when data is saved to a custom field that the user does not have access to

Currently if civicrm_contact_add() (and presumably any other API *_add function) is used to save to a custom field, and the current user does not have the "access all custom data" permission (or an enabling CiviCRM ACL I'm presuming), the contact is saved successfully and the returned contact looks something like:

array (
'contact_id' => '19679',
'contact_type' => 'Individual',
'custom' => array (
),
'is_deceased' => false,
)

no errors are thrown. This is not very developer friendly since there is no obvious way to know that this perm is required.