Here is a fictional story based on this question.
Andrey is a Russian programmer residing in Germany who makes regular wire transfers to his father, Boris, who resides in Russia. Chris & Dasha, a married couple, also reside in Germany. Dasha is Russian and would like to wire money from her Russian bank account to her husband's German bank account.
Pictorially, we have two international transfers.
However, if Andrey and Chris became acquainted, we could have two intranational transfers instead, as depicted below. Boris and Chris would receive the same amounts as before.
Would this be legal? I am interested not only in the pair of jurisdictions Germany-Russia, but also UK-Russia, US-Russia, or X-Y in which jurisdictions X and Y are chosen so that this thought experiment is interesting (in some sense).
Some thoughts and other (subsequent) questions:
If Andrey and Chris do know each other, Andrey's transfer to Chris can perhaps be viewed as a donation to an acquaintance. However, Dasha does not know Boris. Could her transfer be viewed as a donation as well?
If Andrey and Chris do not know each other but only know of each other, Andrey's transfer to Chris is somewhat equivalent to Dasha's transfer to Boris, though subject to the laws of Germany.
It certainly is not the case that these intranational transfers are payment for goods or services. If they cannot be viewed as donations either, could they be viewed as money laundering?