Laws passed during the era of the New Deal prohibited the use of prison labor with the exception of state institutions. However, lobbying by corporations eventually allowed them to use prison labor by 1979, and by 1995 businesses won exemptions from minimum wage laws which permitted them to exploit prison labor for, according to Elizabeth S. Anderson, "mere pennies an hour." She adds that "many are forced to work in unsafe conditions without protective equipment, because workplace health and safety laws do not apply to prison workers."[39]
My understanding is that this is contentious, and some scholars believe that the invasion was truly done to expand territory (not an uncommon theme in world history) and/or that the hierarchal system in Tibet, while inequitable, was hardly comparable to the Western model of slavery. So just be careful I guess?