But it's not only guest workers. It can be citizens. It can be wherever there are remittances.
My mother was born and raised in the U.S. She adopted a family in Uganda that she has helped support for a long time. She sends them money. She can only send them money when she finds somebody who is actually going to Uganda. And she worries about whether it ever gets there.
Remittances apply not just to foreign guest workers. It's the whole range of who the remittances are coming from in developed countries and why.