Be careful about the alcohol. Make sure your model release contains at least one recital that the model has not been supplied any controlled substance (including alcohol) by you before signing the model release, and that he is not under the influence of any drug or alcohol.

Beyond that, if a controlled substance is provided during the duration of the shoot, and something occurs that would cause a health or accident risk, or create a incident of ridicule, you could be the subject of legal action.