Good idea to contact Credit Card company before traveling

I've had mine locked down for purchasing fuel in a different, nearby town. When we've planned holidays long distances from home we've called the company to let them know our plans. However, we've been told that there is no way that they can guarantee that our cards won't be locked down as the computer system that they use still picks up on 'unusual/out of the ordinary' purchases. Thus, for us, calling the cc company has been a crapshoot.