Last year there was an incident in Jerusalem among the "Cult of the Veiled Ladies" in which the police raided the wedding of a 17 year old groom and a 13 year old bride. Such weddings of underage minors are illegal. When the police raided the wedding, most of the people present scattered and ran off to avoid arrest, while the bride and some of her female escorts were detained for questioning. As well, the police raided the wedding before the ring was placed on the finger of the kalla.

The wedding was against the wishes of the father, and he was not present and was supposedly not even aware of it taking place. After this happened, the father went to a beis din in Jerusalem and asked what his daughter's status is - if married or not, does she need a formal divorce? can she later marry anyone, including a kohein?

The dayanim on the rabbinical court investigated the matter and questioned people whow ere present at the time. They were convinced that the halachic part of the wedding had not yet taken place before the police broke it up. As well, theysaid that the chosson, the young man standing beside her under the chuppa, had never before spoken to her at all, not a single word - not about the wedding/marriage and not about anything else. After discovering all this information, and upon further deliberation and debate, the rabbonim paskened that the young woman was not ever married and would be allowed to marry in the future without the need for a gett.

The beis din decided that she had a chuppa but no act of kiddushin, so she retains her status as being a single unmarried woman.

Another issue the beis din had to deal with was whether or not there was a "kol", public knowledge that she had been married. If such a kol goes out, it is enough to require a gett to dispel the rumors considering her married, even though she was not actually married. The beis din decided that while the wedding was the talk of the day around Israel and especially in her neighborhood of Mea Shearim, but they were actually talking about how the police raided the wedding and what happened and not about how she had actually married. Ergo, no formal divorce is needed even if just to dispel any rumors.

source: Ynet