It's even easier than that. If they receive welfare in any form, they are not allowed to move cash outside the country.
If they have received too much, we've over assisted them. Therefore, we want it back.
Return external transfers from recipients to the agency granting the assistance and reduce or terminate their benefits.
Using welfare as an instrument of foreign aid should be policed on both ends and any country that doesn't cooperate loses it's official assistance in favor of it's corrupt assistance, which will be rooted out and eliminated.