回複：請教小白兔，射線及其它明白人．一般來說，拿到綠卡後

To my understanding, XBT & SheXian got such a conclusion mainly based on reasoning. Laws do not come from mathematicians. It doesnot always follow human's logic. It is the compromises of all stakeholders' benefits at meantime.
The logical reasoning can always give you some senses, but you need to confirm with a real lawyer -- I agree with "aftercard".