I disagree. Traveling to Mexico and other Central American countries is worth the relatively small risk. You and your family will experience things that the T.V. and laptop cannot compete with. When you return, you will have both memories to cherish and a new appreciation for the U.S.
Be smart. Leave the fancy clothes and jewelry at home. Abide by local laws and customs. Be aware of your surroundings and use the buddy system. You are more likely to be tricked into paying too much for a product/service (if you go to an all-inclusive resort, you'll be screwed from the start) than you are to experience violence.
We have a degree of danger no matter where we are. While leaving the U.S. means leaving a certain amount of security (or perceived security) behind, there is much to be learned and enjoyed.