The big issue that I see with 'allowing' the whole body to lift off is, it then becomes an unpiloted drone. If they were designed to blowup in two pieces ( UNTETHERED ), then you'd have 2 unflyable chunks of nonaerodynamic blobs that won't go very far. In this particular incident, the body blew in 2, so without the tethers, it wouldn't have been a contained blow.