Hi again,
I pulled in some extra help for this.
If you use the following snippet, that will change the security code for your RSVPs.
add_action( 'event_tickets_rsvp_attendee_created', 'change_rsvp_security_code' );
function change_rsvp_security_code( $attendee_id ) {
update_post_meta( $attendee_id, '_tribe_rsvp_security_code', 'REPLACEMENTCODE' );
} );
You will need to create a function that generates your unique security code and call that instead of having there ‘REPLACEMENTCODE’.
You can use that as a base to change the codes for tickets selling WooCommerce if needed.
Hope this helps.
Cheers,
Andras