In light of court cases holding bartenders liable for serving alcohol to someone who is drunk, should the state be liable for selling lotto tickets to gambling addicts?
This is an interesting problem and hinges on the difference between a current state of an individual and a predisposition. A bartender can be expected to identify obvious symptoms of drunkenness and withhold alcohol. On the other hand, a bartender could not be expected to diagnose an underlying predisposition to alcoholism. In other words, if an alcoholic who is perfectly sober at the moment, walks into a bar and orders a beer, the bartender is not expected to somehow divine the underlying medical condition and refuse the person the beer.
Similarly, there is no way that someone at the counter of a convenience store selling lotto tickets could reasonably be expected to diagnose gambling addiction in a customer who asks for a lotto ticket along with a soda and bag of pretzels, for example.