Client login feature enabled:
#main #client-login .custom-form #sb_terms_and_conditions .promotions-letter-flag label[role=button]{
    display: none;
}
Client login feature disabled:
#sb-main-container #main #sb-timeline #steps #details .detail-step-wrap .detail-step .license-links-container .promotions-letter-flag label[role=button]{
    display: none;
}