Although knowingly providing a fake social security number when one has any expectation of gain is, I believe, a felony.
42 USC. sec. 408.
Indeed.
Except that this only applies to official uses. Obtaining a gain from a particular SS "account". I don't think it applies if you lie to your employer.
Plus, should one "just make a number up," odds are good that it "won't compute," that is, that it will either collide with an existing number (and identity, and reported income) or that it will fail the checksum/allocation tests.
No checksums involved (scheme invented in the '30s before that sort of thing) but there are unused ranges and geographical ranges. Freeware program like ssn.exe (available in all the usual places) will let you vet numbers.
The IRS imposes penalties for faking SS numbers. (Not to mention the punishment meted out by the Sturmgruppenfuhrers of the SS!)
If you use a "wrong" SS# on a W-4 form you will (some of the time but not always) receive a computer generated note from the SS warning you that your earnings have not been deposited into the proper account and if you don't correct the error you may lose benefits. Further action almost never occurs. Obviously more of a problem if done on 1040 forms.
A simple transposition of two digits may not get you zapped, but a large-scale transposition or outright falsification will. If and when they catch up with you.
In the case of a school or cable TV company or something that wants the SS# to use for ID or credit purposes, nothing bad is likely to happen even if you are "caught". The SS doesn't verify SS#s for the credit agencies these days so they've had to build their own databases. If caught by private parties, all you have to do is say, "the SS# is Mark of the Beast mentioned in Revelations. It is part of a Satan-inspired One-World-Government Plot to establish *His* rule over the earth. I will not abide it." They leave you alone after that. Civilians are remarkably easy to cow if you express strong opinions. Real dialog from September 1983 in a Midwest State: Officious Intermeddler: "Why aren't you in school?" 12-year-old girl: "My daddy doesn't believe in sending me to those schools. He says they're controlled by Communists." Almost real dialog from the Spring of 1996: Parent: "My child has no SS# because (he/she) has lived overseas for (his/her) entire life." College admissions bureau-rat: "But how can (he/she) have a Passport without an SS#?" Parent: "That's our problem, not yours unless you've joined the State Department in the last 15 minutes." Most SS# problems occur in cases where one interacts with official persons. Since it is rarely necessary to interact with official persons, one can easily minimize these problems. Don't return their phone calls to your voice mail. Don't go to their offices. Like Rumpole of the Baily with his letters from Inland Revenue, drop their notes into the circular file. Don't ask, don't tell. Very little prison time has (yet) been served for SS# fraud. This may change if the "Immigration in the National Interest Act of 1996" passes since it increases penalties for uttering false documents in some cases. It doesn't apply to your interactions with your cable company. DCF