I occasionally contract with Guru.com and/or Upwork.com. As part of the process to become even a nonpaying member, they ask you to provide your SSN and usually ask you to provide a W9- as would an employer.
However, they are not an employer. If I do work for you through Guru.com, what you do is deposit money in a Safepay account from which I get paid when I submit and you approve my hours.
I did not do work for Guru.com - I did work for you. My question is: If that is the case, is it legal that Guru and Upwork demand a freelancer's social security number, a W9, 1099 and even sometimes a photo ID?