You can go to any area of the Country and find drug related problems. Some of the larger City slum areas seem worst. It is a problem we really need to get a handle on fast. It seems like every morning the news has a new killing in Fresno. Sounds like most are gang related.
As others have said watch your environment, be aware, and stay alert. I would still cruise and enjoy Mexico. I think I would take ship excursions. I would not do my own thing. There is safety in numbers.