s2_allow_site_switching

This hook is for Multisite installs. By default this is switch off to suppress sending emails when Multisite switches blogs and copies over content from one blog to another as this can result in duplicated emails. You can choose to reverse the default setting if you wish.

function my_site_switching() {
    return true;
}
add_filter('s2_allow_site_switching', 'my_site_switching');