We don't know how many were taken discreetly (perhaps lesser known people), but the case that caused much concern was the bookstore owners disappearances [1].

Owners of a bookstore that sold PRC-censored books were taken to China secretly, trialed and convicted. One of them was even a Swedish national, but the CCP insisted he was "Chinese". He released a video "admitting" to his crimes of drunk driving a few years prior but his name in the records didn't even match his actual name, i.e. he was obviously forced to admit to a crime he didn't commit. Another one reappeared in Hong Kong, said he would take his family to China, praised Chinese living quality, and went back to China.

When the law is passed, the CCP doesn't need to abduct people discreetly anymore. They would simply order Hong Kong's officials to transfer them. In short, once this law is passed, no one is safe. Not even foreigners.

[1]: https://en.wikipedia.org/wiki/Causeway_Bay_Books_disappearan...