I would change the text: "If you do decide to drink, DO NOT Drive. Drink Safely." to simply "Always drink responsibly." and have that section of the text be a link to a new page with a paragraph about drinking and driving. You also might include some external links on that page (MADD, AA, etc).
It is more direct to use a command instead of a conditional and use a positive instead of a negative.
It is worth noting that "Always drink responsibly" is the alcohol industry's PSA slogan. It was almost certainly chosen because it contains "Always drink" as opposed to being effective. This is why you see it in industry supported ads instead of the MADD ads.
The industry may have created that phrase in a conveniently ambiguous way; still, in English, positives are always better than negatives when giving a command. Consider the difference between "I don't eat junk food" and "I always eat healthy foods." The first contains the proposition that you have the capability of eating junk foods; the second does not.
Perhaps "Always Drive Safely" or "Always be Responsible" as the link text would be better?
I completely agree that the message "Always drink responsibly" is focused on escaping legal problems while getting customers to drink more. That said, this site has exactly the same goals as the alcohol industry - to get their clients to drink more, and use this product in conjunction with that drinking. So, perhaps "Always drink responsibly" is actually what they want.
It is more direct to use a command instead of a conditional and use a positive instead of a negative.