Here’s Why You Shouldn’t Write “See ID” on the Back of Your Credit or Debit Card
It's still a fairly common practice to sign the back of your card "See ID". The idea here is the merchant will ask for your ID to protect you from fraud. I was having this discussion with a friend recently who did that with all of her cards. When they were stolen, the fact that her signature wasn't on the back didn't matter one bit. Creditcards.com agrees and says the old protection mechanism is ineffective and outdated.
Should merchants check the back of your card for a signature of some sort? Yes. Are they required to? No. How often do they do it? Not very. I had "See ID" on the back of my card for years and rarely got asked to show any sort of credential. If you don't sign it at all, well that's just a rookie move. That allows the thief to sign it and use it as much as he/she wants until it's shut off.
If it makes you feel better to write "See ID" go ahead, just make sure you also sign the card with your signature.
Now we wait for cards where generic pen ink actually works in the signing area......someday, maybe?