Under Trump the expedited removal has no limitation on time period or distance. Anyone in US can be detained anytime, anywhere. Upon detention, the person is allowed to speak with an immigration agent which has become just another ICE agent. If the detainee claims he has proof of citizenship or documentation and the agent believes him, the agent may delay his deportation a few days so a family member or friend can produce the document. There is no right to make phone calls, or contact an attorney. Everything depends on pressure to deport, number available agents, and number detainees.
I believe it is very likely people who were legally in the US got deported and that includes US citizens. Without some form of due process there is just not enough safeguards against deporting the wrong people.