Does your CAC have to be updated to reflect current rank?

Now when I was laterally promoted to First Sergeant, I did not get my CAC changed to reflect the new rank, because I knew eventually I would not be a First Sergeant anymore. But I believe it should be updated with every promotion. Though I wish I had a CAC that had Specialist rank on it so when I go to the golf course, I don't have to pay as much.

Neg. You have to update your ID to reflect your rank. Otherwise when going through the sentry at the gate, you are wearing a pay grade higher than the ID gives, it throws up flags for the sentry; thinking that you have a fake ID (given, that's not the case but there has been stories told). Also for Navy folk, getting onto a ship and going through the quarterdeck, it can sometimes raise alarms too. Plus when you have a senior enlisted looking at your ID.
Just have it updated when you get promoted; save yourself the bullcrap.

It was my experience in that you did not update your CaC until you reached E5 because, as you stated, the change in the Geneva Convention Category. I do not see a problem with this for E1, E2, or E3 but I do think when you are promoted you should get a new CaC card because it shows great addition to detail and wanting to ensure all your issued gear, including ID Card are maintained.