For data with a very strong correlation between the input features A and the output labels B, the turning point below which performance is spuriously high occurs at around κ = 0.55 (Figure 3d), a value the community holds to be pretty low but which is not unknown in published work.
when the underlying relationship to be learned is moderate or strong (Figures 3b and 3c), the spuriously high results already occur for κ values commonly held to be tolerable.