It looks like this was planned and not installed yet.
In ver 1.3.6 admin/includes/languages/english
I see:
define('ENTRY_EMAIL_HTML_DISPLAY','HTML');
define('ENTRY_EMAIL_TEXT_DISPLAY','TEXT-Only');
define('ENTRY_EMAIL_NONE_DISPLAY','Never');
All I did was go to admin/customers.php and change the following:
in admin/customer.php around line 790
Change this
} else {
$email_pref_text = ($cInfo->customers_email_format == 'TEXT') ? true : false;
$email_pref_html = !$email_pref_text;
echo zen_draw_radio_field('customers_email_format', 'HTML', $email_pref_html) . ' ' . ENTRY_EMAIL_HTML_DISPLAY . ' ' . zen_draw_radio_field('customers_email_format', 'TEXT', $email_pref_text) . ' ' . ENTRY_EMAIL_TEXT_DISPLAY ;
}
to this
} else {
$email_pref_text = ($cInfo->customers_email_format == 'TEXT') ? true : false;
$email_pref_html = !$email_pref_text;
echo zen_draw_radio_field('customers_email_format', 'HTML', $email_pref_html) . ' ' .
ENTRY_EMAIL_HTML_DISPLAY . ' ' .
zen_draw_radio_field('customers_email_format', 'TEXT', $email_pref_html) . ' ' .
ENTRY_EMAIL_TEXT_DISPLAY . ' ' .
zen_draw_radio_field('customers_email_format', 'NONE', $email_pref_none) . ' ' .
ENTRY_EMAIL_NONE_DISPLAY ;
}
I inserted the last option "NONE". When I go into Admin, bring up the Customer and click Edit, I can set this to put NONE in the database.
One cleanup would be to make this a dropdown box and to initially set the item to be whatever the database is currently showing as the value. In this case, when a person is set to NONE and you bring up the screen, NONE is not shown as the current value.
Aloha from Hawaii! (its a dirty job, but SOMEBODY has to live here...)