Another category of people affected is ordinary tourists:
www.theguardian.com
There's also a British tourist mentioned in that article.
Note in at least some of these cases, they were stopped at the border, and not turned back, but explicitly taken into detention. In Jessica's case, they only got out when they did because people noticed they were missing and started making calls. Under this ruling, they could ship them off to, say, Sudan as part of a large group with others at that same detention center before anyone could step in.
More on that first case mentioned in the quote:They include another German tourist who was stopped at the Tijuana crossing on Jan. 25. Jessica Brösche spent over six weeks locked up, including over a week in solitary confinement, a friend said.
On Feb. 26, a tourist from Wales, Becky Burke, a backpacker on a trip across North America, was stopped at the U.S.-Canada border and held for nearly three weeks at a detention facility in Washington state, her father, Paul Burke, posted on Facebook. She returned home Tuesday.
On March 3, Canadian Jasmine Mooney, an actress and entrepreneur who had a visa to work in the U.S., was detained at the Tijuana crossing. She was released Saturday, her friend Brittany Kors said.

German tourists’ ordeal reportedly ending as they are returned from US detention
Jessica Brösche to join Lucas Sielaff, who is reported to have returned to Germany on 6 March
Note in at least some of these cases, they were stopped at the border, and not turned back, but explicitly taken into detention. In Jessica's case, they only got out when they did because people noticed they were missing and started making calls. Under this ruling, they could ship them off to, say, Sudan as part of a large group with others at that same detention center before anyone could step in.