Posted a reply to Sabre isn't stopping spam / robot registrations, on the site WordPress Support Forums:
SABRE can't block cheap Chinese "mechanical turks" paid a few cents per registration.
6 years ago
Posted a reply to add_action and set_role, on the site WordPress Support Forums:
The action set_user_role would accomplish what you seek. It is called in wp-includes/capabilities.php
7 years ago