It just feels a little overboard, given how her situation was presented in the Rebirth issue, to throw her in Arkham with the worst of the worst as far as crazies and Supervillains go.
If she used her telepathy on anyone or tried to use it to help people understand her intentions, maybe that's why she was shipped off there?
She was talking to Maggie in that Rebirth issue, who as of Rebirth is back in Metropolis and head of the Special Crimes Unit, so I assumed she was arrested in Metropolis. Which would make sense what with her looking for Superman.