Can one detect a non-smooth null infinity?

It is shown that the precession of a gyroscope can be used to elucidate the nature of the smoothness of the null infinity of an asymptotically flat spacetime (describing an isolated body). A model is proposed for which the effects of precession in the non-smooth null infinity case are of the order r^-2ln r. In contrast, in the smooth version the effects are of the order r^-3. This difference should provide an effective criterion to decide on the nature of the smoothness of null infinity.