Seems like a stupid threat anyway; the fact that you have a history of alcohol abuse does not mean that you were impaired when the incident took place, and it doesn't mean that the store was maintaining a safe environment for its invitees.
It doesn't matter. All you have to do is suggest the plaintiff is an alcoholic, and let the jury infer the rest. Ad-hominen attacks are par for the course in trials, because they are incredibly effective.
Let me repeat myself: Vons was not allowed to bring up the information about the plaintiff's alleged alcoholism. The jury would not have been allowed to hear this information in any court unless Vons could have shown (to the judge, before trial) that alcohol played a direct and immediate role in causing the plaintiff's injury.
But if the plaintiff was an upstanding member of the community, then the threat to publish alcohol sales - even if he wasn't an alcoholic and they weren't unreasonable - might be enough to convince him to drop the suit.