Muhajir bin Ikrimah says: When a proposal of marriage came to the Prophet (peace and blessings be upon him) for one of his daughters, he would come to the curtain and say: "So-and-so is proposing to so-and-so." If she moved it (the curtain), he would not marry her (to him), and if she did not move it, he would marry her (to him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13709