

It has long been used as a transitive verb. The Oxford English Dictionary has collected examples going as far back as 1897 using it generically to make something disappear, but this particular meaning, of government officials forcibly abducting a person and not explaining where the person went, really started to pick up by the 1960’s. The novel Catch-22, published in 1961, had a character use it in the transitive way, with the protagonist complaining that it wasn’t even proper grammar. And that novel was popular enough that it started to appear a lot shortly afterwards, in magazines and newspapers and books.
Most of them say they had valid visas or work authorization.
The U.S. has a visa waiver program where people can come into the U.S. without a visa, and have certain rights similar to visa holders. Many of the South Korean workers have taken the position that the visas they had that allowed them to work for 6 months, or the visa waivers they had entitled them to do temporary work for less than 90 days, and that they were within those time windows.
The lawsuits being filed also allege that immigration officials acknowledged that many of the workers did have legal rights to work, but that they were deported anyway.
So no, I don’t think it’s been shown that the workers did anything illegal. It really sounds like ICE fucked up by following a random tip a little too credulously.