Because it is difficult to identify the person because an offence may use the name of another person to contact or rely on technology in a not disclose wrongdoings.
Because it is difficult to ascertain the offender. The perpetrator may use another person's name in the contact. Or technology in undisclosed offender.
Because it is difficult to find the perpetrators. Because the offender may use other names in the contact. Or rely on Technology in not disclosing the infraction.