With 14 killings in 36 hours in Cancun, tourists urged to be cautious   A rash of homicides is raising concerns about the safety of tourists in the popular getaway destination of Cancun, Mexico. In a span of 36 hours, 14 people were killed in the city. "Cancun is considered an area where the American people should exercise some caution," advised Carlos Gonzalez Gutierrez, the Consul General of Mexico in Austin.  With this wave of violence, some are now debating their upc