FYI, the last four digits of your SSN are the only ones that are difficult to guess. The first five digits can be guessed pretty accurately based on your date and location of birth.

http://www.heinz.cmu.edu/~acquisti/ssnstudy/

That was a really bad move on your part. Could be social engineering. Collections agencies don't need to confirm your social before making a collections call.

I actually make them tell me my ssn. I took a call like this from a collector once. There is another person with my name who skipped on his verizon cell bill. I've never had a verizon cell. I was polite; he was a bit aggressive, but I simply explained the fact that it couldn't have been me. I didn't reveal anything about my info.

I then called verizon and confirmed with them that they didn't have a record of me (but yes had someone with my name). They confirmed he had a different ssn.

I then wrote a letter to the agency telling them that a 2 minute call to verizon would confirm that I wasn't their man. I told them that I consider their failure to do so was negligent, and I would hold them entirely responsible for any damage to my credit rating.

My credit rating was not affected- but it may have had nothing to do with my letter.

Exactly, what's the point of a security check if they keep asking you until you pass.

I had a similar experience when I tried to redeem some Travelers Cheques. Clerk claimed signatures wouldn't not match, and wanted me to sign again at the back of the Cheques. She handed me slip of paper and asked me to practice before I tried again.

I was baffled but certainly preferred that over being arrested;-)

My dad hadn't signed his credit card, so she handed it back to him, told him to signed it, took it back -- and _compared_ the two signatures.

The only reason this kind of behaviour makes any kind of sense is if she (and the clerk in your example) were just going through the motions and didn't actually care about the security.

If a card is invalid (i.e. no signature), the cashier can ask for identification to verify your identity, and watch you sign. If the card is already signed, cashiers may not ask for ID as a condition of the sale, the transaction is considered valid if the signature on the card matches the signature of the receipt.

If your dad had simply signed the card prior to walking up to the counter, that's all the cashier would have been able to verify. So yes, card security is rather lax if it's not signed by the owner of the card immediately upon receipt.

I know this random information because I was a bit miffed that Walmart rejected my girlfriend's transaction because she did not produce ID with a signed card. The above applies to the Visa merchant agreement, I'm not sure about Mastercard or American Express.

Also -- "SEE ID" is not a valid signature, though you can write that over your signature and the card is valid. However, cashiers are not required to honor it.

  > the transaction is considered valid if the
  > signature on the card matches the signature
  > of the receipt

In the example above, both the receipt and the card were signed at the register. It would be extremely odd if they didn't match, even if the person paying was a fraudster, therefore it's odd for her to verify them.

Maybe to avoid chargeback.

What else could she do? At least she prevented future variations of misuse of the card.

Sure, except that it makes no sense to then compare the two signatures.

Why did you give out those 4 digits? Really, I would have never ever done that. If they want to confirm and they're calling you then they should authenticate themselves, not you!

Did you not even ask who was asking?

She gave me the name of the collections' agency and her own first name.