The most likely problem with the offer, which the magus characters in our saga might suspect, is the following:
Could House Mercere leadership be pollyannish enough to try isolating the mundane humans outside of covenants from the other Houses and thereby monopolizing mundane relations?
Our magus characters' mundane relations are far more articulated than just business deals, and some of them pursue plans for further integration of the Order with the mundane world.
But one of them is a Mercer Portal builder: so they could ask him about the likely motivation of House Mercere leadership.