Referback signup question

I signed up with Referback a few days ago. This morning they sent me an email to welcome me to the program (thanks!), but they also want me to confirm some information:

For security reasons, please confirm the following information which was submitted upon registration:

First name:
Last name:
Email address:
Physical address:
Telephone number:
Date of birth:

I’m wondering, is this really necessary? I have signed up with quite a few affiliate programs in recent months, and this is the first time I have been asked to do this. Why is Referback the only one to have this requirement? Asking me to send my personal information twice is slightly annoying — once should be enough. (It is for every other aff program).