Some of them sit there and throw out the Levitical laws around as if they are under that old covenant.
I find it interesting that some believed that Exodus 22 condones pre-marital sex. I for one do not believe it does, but lets pretend it does and see exactly how you would follow that law (remember you have to follow the law perfectly, if not, then you are at fault for breaking the whole law)
"If a man entices a virgin who is not betrothed, and lies with her, he shall surely pay the bride-price for her to be his wife. If her father utterly refuses to give her to him, he shall pay money according to the bride-price of virgins." (Exodus 22:16-17)
First off, this verse only apply to man whom is [enticing] a virgin whom is not betrothed. Secondly, the guy has to marry her unless the father refuse. And third, the guy has to pay the bride-price (married or not). So if someone wants to keep this law and say that this law condones pre-marital sex, then you have to abide by the entire thing. And while you are at it, you have to abide by the entire old covenant, thus making Christ's crucifixion void.
An even sadder case is this, If you take the idea that the man does not marry the woman, she is no longer a virgin, lets say she gets married to another man. In Deuteronomy 22:13-21, if another man marries her and then sleep with her and find out that she is not a virgin, she can be put to death. And if you read Deuteronomy 22:22-30, starting in 23-24 "If a young woman who is a virgin is betrothed to a husband, and a man finds her in the city and lies with her, then you shall bring them both out to the gate of that city, and you shall stone them to death with stones, the young woman because she did not cry out in the city and the man because he humbled his neighbor's wife; so you shall put away the evil from among you.
If someone says it's not the same situation as Exodus 22, then Deu. 22:28-29 might help:
"If a man finds a young woman who is a virgin, who is not betrothed, and he seizes her and lies with her, and they are found out, then the man who lay with her shall give to the young woman's father fifty shekels of silver, and she shall be his wife because he has humbled her; he shall not be permitted to divorce her all his days."
And the stipulations are the same as Exodus 22, except there is no father clause. But either way, you do it before marriage, and God considers her your wife! You have sex with someone else afterward, then that is adultery! If you think pre-marital sex is not a sin, well men, that's your option. Now where does that leave us women?