I used my name with an incorrect B-day to test out if the verification was real, and they did contact me regarding that issue and asked for the last four of SSN.  Sorry, not happening when I'm on date-check and other sites.  They should use those.  There are other ways to get screened, none requiring SSN or any part of it.

Who they use for verification - unknown - as I did ask and he was reluctant to tell.