Probability ﹩{P}_{\mathrm{SDSS}}﹩ that all the remaining 51 sources in the SDSS sample have magnifications ﹩{\mu }_{i}\lt \mu ﹩. Assuming the presence of one source with ﹩\mu =450﹩, it is nearly impossible, e.g., ﹩P(\mu \lt 10)\sim {10}^{-5}﹩, that all of the remaining sources are not magnified. The values discussed in the text are indicated with red dashed lines.