My mom used to tell me to write CHECK ID in the signature block. Someone only ever asked me once. It's probably been like 10 years since I've signed the back of a new card. An older woman at an antique shop actually checked for a signature and made me sign it in front of her.

If you look at the credit card agreement, a card isn’t (or at least wasn’t) authorized for use unless it had an actual signature. “Check ID” and such are cute, but really only mean that the card is unsigned and thus invalid.

The fact that a signature is, to date, a legally binding form of identification is baffling to me to be honest. More and more is digital these days, but still.

(my "signature" is just a squiggle based on my initials and I can't reproduce it consistently)

It's not legally binding if you didn't sign it, but that won't stop someone from trying to claim that you did.

I was telling my lawyer a couple of weeks ago that I wasn't even sure I could do it consistently any longer and actually practiced a bit before going to the office. She basically said "Do the best you can" :-)