In addition, there were less well-known procedures that led to deportation of Chinese immigrants. Long before 2012 Presidential candidate Milt Romney advocated "self-deportation" for dealing with the immigration issue, such a mechanism already was available for a Chinese who wanted to be deported! However, you could not just leave the country but first had to complete an application form for the U. S. Department of Labor.
Consider the case of 85-year old Oung Don You in New Jersey who entered the U. S. at age 14 as a laborer in 1893 but in his old age become dependent on public assistance. In 1941, which was not exactly an ideal time to return to China in view of the war with Japan, he voluntarily filed for 'removal to native country' and was promptly deported.
Inasmuch as Oung was destitute, his passage back to China was probably at the expense of the Immigration Service. Perhaps that was why he had to first complete the application form.