回复：家门不幸，限制B2签证入境的问题，多谢体谅！

恳请版内朋友建议，如何限制他们在今年8月前再次入境美国？我不会提供他们任何的新的担保或邀请。可以报告给哪个政府机构（custom, immigration, or counselor）表明我不再担保吗？
-You can not stop them to enter U.S. because they have a valid visa.

不知美国的限制令（restrain order, based on mental abuse）可否通用于未入境的人士？
-No such a law in your parents'case. But you can ban them to enter your house from the law point of view, but I do not think you will do that.

家门不幸，多谢大家的体谅！