After leaving the after-hours drinking session on March 22, a ''severely intoxicated'' female casual employee was allegedly the subject of a ''serious offence'' by two men who left the bar with her, the authority said in a written decision.
Another female employee had earlier tried to get the woman in a taxi, but the taxi driver refused to give her a ride.
The casual employee earlier took part in drinking games, after she, duty manager Paul Feary, the other female staff member and some unidentified others stayed after the bar closed.
Mr Feary was one of a few people with access to the Lone Star's security code, which he gave to a security firm after it was notified by an alarm that people were present after closing time.
Despite finding there was ''no doubt'' the drinking session constituted a breach of licence, the authority decided to take no action.
''In this case, the authority concludes that the licensee had taken all available measures to prevent such an incident,'' the authority said.
Police had initially sought a penalty in order to send a message to the industry that ''such behaviour will not be tolerated'', but at the hearing they recognised that such an order could not be justified.
Mr Feary was dismissed for his role in the breach of licence.