We went abroad last September. I had never bothered to contact CC companies in the past, but decided to do so since security on all credit cards has been increased in recent years. Chase rep (my VISA) took my info and said thank you for letting us know. American Express rep said "we expect our cardholders to travel, no problem here, and no need to notify us."
I used both in Europe during out trip, and the only problems I had were at ATMs, where I sometimes had difficulty figuring out what the machine wanted and how to respond/which buttons to push.
I have never had any problems with any of my cards anywhere in the US in spite of never telling them where I was going. Perhaps this is due to the fact that my cards get used all over the US all the time. I HAVE gotten calls (stupidly on the land-line at home instead of my cell phone, which I'd have with me while traveling) about those usages. The times there has been fraud involved, I've called them, not the other way round.
I highly recommend everyone check all their credit card activity at least weekly, whether THEY call you or not.
