Originally Posted by MeLike2Travel
Ditto what askworldtraveler wrote. The first intl trip I took after obtaining the Citi card (about 2 years ago) my card ended up being blocked a few days into the trip and I had to use my Amex card. When I got back I found a voice mail on my cell phone. Since I hadn't returned their call they had blocked my card. Now I call in advance and never had problems.
if you call citibank before leaving and tell them that you are going to"X" then your card will not be blocked. This takes time but worth it if overseas.!