Picking up the tab. Always the right thing to do?

So on 9 to Noon today we discussed a recent Reddit thread where a man offered to a buy a woman a drink after meeting in a bar. He ordered a beer and told the bartender to "get the lady whatever she wants!" What she ordered was 4 Don Julio double shots at $75 a piece. She then told him they were for her and her friends, patted him on the back and returned to her table. Surprised the man left a $10 bill for the beer and told the bartender she was paying for the shots! The woman was visibility upset and later we learn her boss is the man's mother!! After all the drama he still refused to pay her bar tab. Should he? We discuss along with NFL rookie dinners that went horribly wrong.