The fact many (note: not all) of those crossing via this means are intercepted and processed through an administrative process does not make it controlled migration.
About 3000 were forcibly returned between June 2020 and June 2021, although the vast majority of those (2,809) are people convicted of a crime. Few non-criminals are forcibly returned to their point of origin once they are in the country, regardless of their immigration status. Three-quarters of people who enter immigration detention after illegally entering the country are released into the population without being returned.