Social media accounts aren't required, what's required is demonstrating identity.
Social media is just one way of providing information that can be used to verify someone's identity. If someone doesn't use social media they can use other methods like providing a mobile number that we can verify via SMS, or providing and emailing from a work email address, or any other method they can think of.
If they thought that was required, I should maybe tweak the wording so it is more clear.
More info:
http://forum.calgarypuck.com/showthread.php?t=140522
If someone registers and their Facebook account is brand new then that won't do much to establish identity, so we won't use it to approve an account.
Not sure how to protect against burner phones.. maybe re-verify a mobile number six months after registration?
EDIT: I tweaked the wording on the field to hopefully make it clear that social media is just one option, that identity verification is the goal of the information provided.