Well at least according the the legislation prior to Vatican II, which the SSPX insists on following; A priest who blesses a religious item such as a rosary must have faculties to do so by his superior or the Local Ordinary. To erect the Stations of the Cross, Consecrate a chalice and paten, etc he had to have a special indult from the bishop to do so at least prior to reforms made to the Rituale Romanum by Pope John XXIII.
Prior to the reforms only Franciscans or a bishop could erect the Stations unless the bishop granted the priest faculties to do so. Same with several other blessings that were referred to as Reserved Blessings.
Someone else can better answer the current legislation of the Church which I’m not as well versed in, but based on the old code, the SSPX by persisting to resist the efforts of the Holy See to be regularized the Society is placing themselves and their lay followers in a very questionable situations. They claim the right to establish chapels, and offer Mass because of an emergency state they percive. By establising and maintaing chapels where either Eastern or EF Masses are readily availible with the excuse that they are responding to the needs of the faithful, they seem to be determining that they are the Church as they make no effort to even approch the Local Ordinary seeking permission or submitting to his lawful authority. Far from an action which responds to a state of emergency, the blessing of a rosary, or enrolling someone in a brown scapular does not fall under a provision of an emergency or something absolutly necessary for the salvation of souls. Which further gives the impression that they consider themselves outside of the legitimate authority of the Church.