This summer my family and I went on a road trip and during the drive we used a credit card to pay for expenses such as gas and food. After several purchases our card was denied. There was no reason for it to be declined so we called the card company and sure enough the card had been put on hold due to the fact that the card was having unusual activity and was "moving."
The card company had called our home to confirm we were traveling but since we were out of town we didn't answer. While we appreciate that our card company was attempting to prevent unauthorized charges it sure was an inconvenience. We now call our credit card company to let them know we will be traveling.
When I researched the subject I found credit cards getting put on hold is especially common with international travelers. If you plan to travel anywhere be sure to call your credit card company and give them the countries and dates you will be traveling.
Keep in mind international transaction fees on credit cards are common when traveling abroad. You will also want to avoid getting cash advances with a credit card while traveling. You will pay a fee to withdraw and you will begin incurring interest from the moment you withdraw. Finally, keep your card numbers and the card companies' phone numbers in your luggage in case you need to report your card lost or stolen.