Simulated test of our method by propagating the positions of 2000 simulated candidates to µ² Sco over four epochs. Half are propagated according to the co-moving model, which just adds zero mean noise at each epoch. The other half are propagated according to the proper motion of background stars, plus noise. The colours denote the logarithmic odds ratio that our method computes for each trajectory. All 2000 are correctly identified.