[@roysmyth Participant 12 years, 4 months ago]

For future consideration.

Please add two hooks in bbpress/includes/common/functions.php after lines 1105 and 1245 to filter the array of user ids.

Something like
$user_ids = apply_filters( ‘bbp_forum_subscription_mail_ids’, $user_ids );
and
$user_ids = apply_filters( ‘bbp_topic_subscription_mail_ids’, $user_ids );