How do You Prove that the Bar Tender Knew or Should Have Known the Person was Intoxicated or Would Become Intoxicated?

It can be difficult to prove that the person consuming alcohol was intoxicated or would become intoxicated.  The chances are good that the bartender will not admit he or she knew the person was drunk.  Usually, evidence from other bar patrons, people who were with the bar patron or police officers will testify as to what they observed.