现在美国对在中美来回跑的知识分子很警惕

"These cases were among more than a thousand investigations the FBI has into China’s actual and attempted theft of American technology—which is to say nothing of over a thousand more ongoing counterintelligence investigations of other kinds related to China. "

https://www.fbi.gov/news/speeches/the-threat-posed-by-the-chinese-government-and-the-chinese-communist-party-to-the-economic-and-national-security-of-the-united-states

告诉你FBI怎么调查你。先注意到你天天中美来回跑，如果你是搞关于通讯，医疗生物等顶端技术，他们会把你的财政调查一遍，应该很容易发现你的mortgage fraud。然后，就拿这些小辫子威胁你，让你供出你是不是偷窃了美国的顶端技术给中国。

很多人认为白色谎话谁也查不出来，那是天真。人家不想去查。但是如果碰上严打，能抓一条鱼就是政绩，那些探员像警犬一样嗅觉灵敏。