> I am reading “potential citizen” as “a detainee who claims to be an American citizen whose citizenship status was not ascertained.”
That's not what it means in this context. The GAO report is based on ICE's own database records, they found 70 deportees that records indicated they were potentially citizens.
> Law enforcement can get things wrong, but I haven’t read of any documented instances of this happening.
Wikipedia has an article that lists documented instances of citizens being removed.
https://en.wikipedia.org/wiki/Deportation_of_Americans_from_...