I appreciate that the discussion on this thread has been in the context of OP generally traveling light, and the speculation of making a few extra $$$.
However, this is virtually a
full-time occupation for many, particularly in the India-Far East and India-Middle East sectors. The only difference seems to be that while OP may be looking at profiting personally, the India scenario is of "traders" engaging a "kurivi" (Tamil for sparrow) to travel virtually empty-handed to their ME/FE destination, and bring back large amounts of goods for local sale (typically in the black/grey markets). And depending on the size of ops of the "trader", there can be more than one "kuruvi". The "kuruvi" gets a fee, airfare, accommodation and living expenses while abroad. The linked article suggests black marketing, but then there are several shades of grey!