From Social Security's own "Program Operations Manual System" -- pay close attention to section "E." :
RM 10205.180 Applicant’s Signature on a Form SS-5 when applicant is not in the office
Ensure that Form SS-5 is signed by a proper applicant. See “Policy for determining the proper applicant” in RM 10205.025B.
A. Number holder applies on his or her own behalf
If the NH applies on his or her own behalf, the signature in item 17 must agree with the Name to be Shown on Card in item 1. For acceptable discrepancies, see RM 10205.180E.
B. Proper applicant applies on behalf of NH
When the applicant is not the NH, the proper applicant must sign his or her own name and indicate his or her relationship to the NH, e.g., John Smith, father. Using “for” in the signature block, e.g., John Smith for Mary Smith, is not correct.
C. Signature by mark
If Form SS-5 is signed by mark, it must be witnessed beneath or beside the mark by at least one person.
D. Signatures of foreign-born applicants
Accept signatures from foreign-born applicants that are in characters other than our standard alphabet without question.
E. Remarks added to signature block
Additional information in the signature block may invalidate the application. Such information includes, but is not limited to, statements that imply the applicant’s refusal to be subject to the penalty clause on the application (e.g., “without prejudice,” “under protest,” or “with reservation”).
If such an annotation is made, do not process the SS-5. Return Form SS-5 to the applicant with Form SSA-L676. In the blank fill-in box indicate that “The application cannot be processed because you altered your signature on the application.”
So, if a reservation of rights is made by the SS-5 application, the Social Security Administration will not process the application or issue a number. In other words, applying for, and receiving, a SSN presumes the applicant has voluntarily waived his rights, BY SIGNATURE. That's a pretty strong presumption in favor of the SSA... and IRS. Oh, and guess what? The SS-5 is an Internal Revenue Service form. Here's an example of an SS-5 from the 1950's:
And gee, whaddya know? Since then they have removed any mention of "Internal Revenue Service" from the SS-5 form: http://www.socialsecurity.gov/online/ss-5.pdf.
They wouldn't do that to conceal the relationship between voluntarily getting a SSN and thus signing away your rights (in exchange for eligibility for benefits), thus enjoying a lifelong, cozy relationship with IRS? No way!