coords.match(), which is also used in mesh.matchCoords and mesh.matchCentroids(), works only if the 2 Coords objects (self and coords) are 2 fused objects. If not, the result can be wrong. In the documentation this requirement is not reported in coords.match and Mesh.matchCoords but it is reported in Mesh.matchCentroids(): "self and Mesh are same eltype meshes and are both without duplicates".
I believe that it should be stated in the documentation that the 2 Coords objects should be fused. In addition I would include a param in the function to raise an error if the input objects are not fused. Something like that in coords.py:

def isFused(self, **kargs):
    return self.points().fuse(**kargs)[0].npoints() == self.npoints()


def match(self,coords,clean=False,checkinput=False,**kargs):
    """..."""
    if checkinput:
        if not (self.isFused(*kargs) and coords.isFused(*kargs)):
           raise ValueError("I can only match fused Coords objects")

Should we do that?