My father remarried last October and his wife's passport is still in her old name. They will be going on a cruise this October and asked my advice about getting the name changed on her passport. I advised to leave it as is. Most cruises don't ask for any other ID and their tickets were purchased in their original names.

Am I correct in believing they would have no difficulty on their cruise?

As for flying which they never have done and are unlikely to do in the near future, would carrying the certified copy of the marriage certificate be enough? Her passport is not up for renewal till 2015. What future problems might they be heading for if they do not update her passport to her married name?

As long as her face and name match, there should be no problem. Many people keep their names after marriage, never changing anything. All of that said, she should carry a copy of every relevant document. That never hurts.

She had her drivers license changed to married name. Wonder if that document should then be left out?

It took so long for me to change my name on my passport when I remarried that the divorce papers were being filed before I got it done

I carried the passport and a certified copy of my marriage certificate and all was well.

Except with the marriage, but that's another story.

Under what thread will that be?

No, bring it along, just in case she wishes to rent a car somewhere. When traveling overseas you can never have too many documents.

Here's what I'd do: (1) Passport is sufficient proof of identity at official places like Immigration, Customs, etc., so just use the passport. (2) If renting a car, etc., where a DL may be required, just use the DL. (3) In case there is a situation where she has to show both Passport and DL, have a copy of marriage certificate handy. Just don't raise the issue yourself. In fact, never raise any unnecessary issue with any bureaucracy anywhere.

When the trip is over and there is some quiet time, she should change the name in the passport. Keep the old name as "alias" or whatever the procedures allow.