DOB made sense because 10,000 people in the world have the same birth date. DOB (without PII) didn't narrow enough to identity the person. Regarding that last 4 SSN, yea I would never give that out.

My doctor office required me to provide my DOB before I can schedule an appointment or questioning over the phone. My pharmacist required my DOB before I can get my meds from them. If I don't provide my DOB, they will turn me away and assumed that I'm a scammer.