The Prophet ﷺ said, "A virgin should not be married till she is asked for her consent; and the matron should not be married till she is asked whether she agrees to marry or not." It was asked, "O Allah's Apostle! How will she (the virgin) express her consent?" He said, "By keeping silent." Some people said that if a virgin is not asked for her consent and she is not married, and then a man, by playing a trick presents two false witnesses that he has married her with her consent and the judge confirms his marriage as a true one, and the husband knows that the witnesses were false ones, then there is no harm for him to consummate his marriage with her and the marriage is regarded as valid.  

عَنِ النَّبِيِّ ﷺ قَالَ لاَ تُنْكَحُ الْبِكْرُ حَتَّى تُسْتَأْذَنَ وَلاَ الثَّيِّبُ حَتَّى تُسْتَأْمَرَ فَقِيلَ يَا رَسُولَ اللَّهِ كَيْفَ إِذْنُهَا قَالَ إِذَا سَكَتَتْ وَقَالَ بَعْضُ النَّاسِ إِنْ لَمْ تُسْتَأْذَنِ الْبِكْرُ وَلَمْ تَزَوَّجْ فَاحْتَالَ رَجُلٌ فَأَقَامَ شَاهِدَىْ زُورٍ أَنَّهُ تَزَوَّجَهَا بِرِضَاهَا فَأَثْبَتَ الْقَاضِي نِكَاحَهَا وَالزَّوْجُ يَعْلَمُ أَنَّ الشَّهَادَةَ بَاطِلَةٌ فَلاَ بَأْسَ أَنْ يَطَأَهَا وَهْوَ تَزْوِيجٌ صَحِيحٌ