This is the issue:
http://www.forumpromocean.com/t326-email-notifications-for-every-reply

Give this code a try:

Code:

jQuery(document).ready(function(){
  jQuery('#cp-main #ucp div fieldset dl dd label input[name="notifyreply"][value="0"]').prop('checked', true);
});

Should be working. However, beware that this will force the option NO, always. The only way the person can switch back to 'Yes' would be by the person disabling the jQuery above manually, client side. This require at least a little bit of skill so probably you'll see 99.99% of your forum members with this option disabled. I guarantee you, though, since the new notifications toolbar came into place there's not much use to the notifications in email. Personally, I always mark these notifications SPAM.

Regards.

So all options marked to send an email as a notification would be disabled? Not just the watch topic?

Hi,

The code modify the profile option of your members inside preferences. As far as I know, only alerts regarding replies are sent to your e-mail. "Sends an e-mail when someone replies to a topic you have posted in. This can be changed whenever you post." I haven't tested it but I believe the person will still be able to receive the e-mails if, when they post, they check to watch the topic.

PS: This only changes the Profile >> Preferences field. It doesn't alter any other setting, including notifications that the user chooses to receive by e-mail, if available. For instance, Profile >> Notifications will still be able to send these notifications via e-mail if the user wants to.

Regards.