Influence of measurement errors or binaries on the cumulative σ_3D. (1) The upper orange curve is the fiducial one from Fig. 1. (2) The dashed black curve shows the cumul. σ_3D when applying a cut on the Gaia RUWE parameter, to test the influence of binaries. (3) The middle blue curve shows the cumul. σ_3D when applying an additional error cut at e_RV ≤ 1 km s⁻¹ on the stellar members of each cluster. (4) The magenta curve shows the cumul. σ_3D when using the cluster medians. (5) The black cross marks the total σ_3D as calculated from all stars in Sco-Cen with valid RV measurements. The error bars (shaded regions) show the 95% interquartile ranges (2σ).