MT 103/23 payment, what is it really.
"Field 23 - Instruction Code" is where the remitting bank (at the request of the remitter) puts in a simple code instructing the beneficiary's bank how to effect the payment, such as "Credit Account under Advice", "Telephone beneficiary on receipt", "Pay against passport" and such like.
MT103 is a straight-through processing mechanism requiring very little manual intervention, except in simple tasks like above.
You cannot send an MT103 with a condition that the beneficiary's bank must receive, say certain documents, from the beneficiary before crediting his account.
Such a request will be rejected by the remitting bank, and if sent in Field 23 (which allows for only a few standard codes) will be rejected and ignored by the beneficiary's bank who will credit the beneficiary's account anyway.
Transactions that involve the exchange of money for documents are documentary collections (D/A, D/P etc.) and are processed in other ways. Banks are banks, they are not lawyers or trust companies