All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
This marriage is void as the Prophet said: "Any woman who gets married without the consent of her guardian, her marriage is invalid, her marriage is invalid, her marriage is invalid. If he consummates the marriage with her, she is entitled to the whole dowry as he made her private parts lawful to him [by having intercourse with her], but if they differed, [there is a dispute among those who want to be her guardian as to whom is more entitled to be as such] then the judge is a guardian for the woman who has no guardian." [Ahmad and Abu Daawood] The Prophet further said: "A woman cannot get married except with the permission of her guardian." [Ahmad and Abu Daawood]
Therefore, a woman who gets married without the consent of her guardian, her marriage is void because the presence and consent of the guardian is a condition for the validity of marriage based on the previous Prophetic narrations, and this is the view of the majority of the scholars.
As regards the punishment for those who are involved in this [got married without the presence and consent of the guardian], their matter is in the Hands of Allaah, He may punish them according to their sin if He so wills, and He may forgive them if He so wills. Allaah says (which means): {Then He (Allaah) forgives whom He wills and punishes whom He wills.}[Quran 2:284]. Allaah further says (which means): {He (Allaah) punishes whom He will, and He shows mercy to whom He wills; and to Him you will be returned.}[Quran 29:21]. So the family of this girl should first blame themselves before blaming the family of the man, because without the consent of the girl [to marry him without the consent of her guardian], that man would not have done what he did.
Allaah knows best.