The fence project is an interesting sign of how the relationship between Saudi Arabia (KSA) and the Yemen has developed. For decades KSA has sought to maintain some control in Yemen, principally by subsides and bribes to many individuals, tribes and others. Now a fence is needed, has this influence evaporated?

I suspect that no Saudi will actually work on building the fence, although IIRC most Yemeni were expelled after the invasion of Kuwait.