Fragments in Livy are often as interesting as his main tale. For example he tells us that
This year the Vestal Minucia first attracted suspicion by her dress, which was more elegant than was proper, and was subsequently charged before the pontiffs on the evidence of a slave. She was ordered by their decree to abstain from performing sacred rites and to retain her household slaves in her power, after sentence was passed, she was buried alive near the Colline Gate, to the right of the paved road, in the Polluted Field- a place so named, I believe, from her unchastity. (Livy VIII 15)
There are three interesting things here that I think deserve us to comment or pause. The first is that Vestal Virgins were supposed of course to be the latter- virgins. They were supposed not to have sexual intercourse- proving that they had or had not had sexual intercourse was not easy. You were lucky if a Vestal became pregnant but sex does not have to result in pregnancy and so that was not an infallible test. Consequently Romans on many occasions reverted to thinking about reputations. In a patriarchal society such a stress on virginity of course was tied to a fear of women and particularly women's adornment and sexuality: this is perhaps what we see with the unfortunate Minucia. My second observation is that Minucia was ultimately suspected because she seemed to behave inappropriately: morally forbidding societies like ancient Rome or no doubt some more modern communities tend to have a totalitarian suspicion of their member's activities. The ancient Romans expected Vestals and women in general to behave chastely as well as be chaste- the commandment to be chaste extended to cover dress and behaviour- the moral code justified a moral judgement on the totality of Minucia's life. Thirdly we have the comment about her slaves which reflects Roman practice- slaves must be kept because they might be tortured in law to reveal evidence- consequently it is not unusual to hear that slaves are not freed when a man or woman is jailed. Torture was a sign of not being free and in the Roman conception, to be subject even to the threat of torture was to be a slave.
Lastly I think we have a just so element. We do not know where Livy got his tale from that Minucia was executed in a certain place- but what we can say is that he seems to have linked it to the 'modern' name for the Polluted fields. In a sense what Livy may be doing here is an ex post facto justification- the field is deemed polluted and therefore a reason for the pollution must be found, we do not know where Minucia was executed so why not here.