One warning recommends tourists to "exercise a high degree of caution" while in Mexico due to high rates of criminal activity and a "deteriorating security situation in many parts of the country." Also, if you're planning on visiting in July, you are at risk due to unpredictable public reaction to the Presidential elections.
The second warning advises against "non-essential travel" to the border areas between Mexico and the United States. Particularly, crossing the northern border by land may subject tourists to shootouts and carjackings.
However the FAITC does offer a registration service to assist travellers should they find themselves in an emergency situation while travelling abroad.
This service and other travel advisories can be viewed at http://www.international.gc.ca/