I guess sometimes when you're clubbing you gotta take a leap of faith. This applies to life. Otherwise there's too many worries in your head to achieve the original goal (what if the alcohol is adulterated, what if this girl just wants to mug me, what if she's got cooties, what if those guys are looking for a fight and oh shit, they're chapo's sons, etc.). I say look only for the best places, take advice from people you trust, and generally avoid putting yourself in a position prone to getting surprises (yeah, don't get shitfaced alone -or don't get: moderation-, don't go to that shady looking place with no customers, don't drink the ice your eyes saw in terror as it was unloaded from rusty old trucks, beware of strangers, etc., golden rules of the conscious tourist).
Now, I understand the health concerns, but I'd also like to share that Corona beer is made with tap water, technically.
What I'm trying to get at, is that if your mindset is that of constant worry (a legitimate one, getting intoxicated sucks), honestly, you might as well do yourself a favor and not visit the place. Or, bring medicine or something.
I get the appeal of visiting Mexico, but many tourists have a false expectation of the quality to price ratio. Many want it all: a nice resort with view to the beach, banging clubs with honeys and alcohol, quality food and entertainment, but they want it cheap and with American standards. We're still developing, and I really hope that in a not so distant future, flocks of Americans fly down south just to drink our tap water. When they run out of water, perhaps.
