Dram shop cases involve litigation against a seller of alcoholic beverages for the over service of alcohol to a customer who injures another while intoxicated. In a typical example, an individual is served alcohol past the point of intoxication by a bar then that individual gets into an automobile accident and injures or kills the plaintiff. Unfortunately, this occurs quite often.
Setting aside the legal justifications for dram shop cases for a moment, let's address the moral considerations. You are probably thinking to yourself that every person is responsible for themselves and that bars have no duty to stop people from drinking. We tend to agree somewhat with that sentiment. There is an inherent friction here; bars are in business to make money and they make money by selling more drinks. However, we are placing on them a duty to serve drinks responsibly, which will undoubtedly include cutting people off. This would be in direct conflict with its goal of making money. However, as anyone who has drunk to excess can attest, inebriated people have very poor decision making skills and frequently cannot be counted on to stop drinking or to not drink and drive. Bars owe their community a moral duty to not create drunken monsters and to not release them into the community.
Society has placed on bars a legal duty to serve alcohol responsibly. Bars must have liquor licenses to sell and serve alcohol. Liquor licenses are granted by the state. In order to acquire a liquor license, bars enter into an agreement to serve and sell alcohol responsibly. Dram shop cases help enforce this agreement. In Texas, bars are partially protected by the "Safe Harbor" provision. The Safe Harbor provision allows bars to escape from civil liability in certain circumstances. As long as the employee who over served was required to attend a TABC (Texas Alcoholic Beverage Commission) alcohol service training program (and the server actually attended), then the bar cannot be held liable for a dram shop case. However, two exceptions apply. If the bar implicitly or explicitly encouraged the employee to over serve, then there is no immunity from a dram shop lawsuit.
Generally, Texas bars require all of its employees to attend the TABC classes before serving alcohol. Further, it would be rare to find a bar that actively encouraged over service. However, many bars implicitly encourage the over service of alcohol. Manuals or training that encourages servers to keep customers drinking can be considered implicit encouragement. Creating a "party atmosphere" and aggressive drink specials can be considered encouraging over service. Suffice it to say, many bars are very aggressive about encouraging over service and thus higher sales.