What occurs to the lower-mass stars in an open cluster as age determination relies on main-sequence turn-off?

They may have already drifted away from the main cluster structure

When using the main-sequence turn-off point on a color-magnitude diagram to estimate a cluster's age, astronomers must recognize the consequences of weak binding over time. Lower-mass stars are much longer-lived than their massive counterparts. As the cluster ages, these less massive stars, which remain on the main sequence for vast periods, can gradually drift away from the main, centralized grouping due to the weak gravitational ties and external tidal forces. Therefore, an observational survey might capture a structure where the remaining visible members do not perfectly represent the original population, potentially skewing age calculations if this drift is not accounted for.