It takes non-design loads off things. Arjan ripped the mount at the base of the mast out of his mast when tightening the diamonds. Probably because when doing up turnbackle the rivets holding it in place were put in tension rather than shear by the lever from his spanner. Had the wires been removed there would have been no load on this fitting during tightening and when the load was re-applied the rivets would have been in shear and possible would have stayed in place..