Bank cards may be frozen. Because after Du Xiaoman files a lawsuit, the court may require the freezing of the defendant's property, including bank cards, in accordance with legal procedures. But this also depends on the specific circumstances of the case and the court's decision. If the bank card is frozen, the defendant needs to provide corresponding asset proof and relevant procedures for lifting the freeze as required by the court. In addition, the defendant can also raise objections or appeals to the court to resolve the dispute within the scope permitted by law. In short, after being sued by Du Xiaoman, the bank card may be frozen, but the defendant needs to comply with legal procedures and safeguard his or her legal rights and interests in accordance with the law.