Eight unruly revellers were handed "yellow cards" on the first night of West Midlands Police's new football-style method of curbing anti-social behaviour in Birmingham.
They were "booked" for minor offences, such as spitting, swearing, dropping litter and urinating in the street.
Their details were logged into the police's database and if they re-offend, they will be issued a "red card" and a court summons.
Some 45 police officers started to enforce the warning system on Birmingham's Golden Mile, which includes Broad Street, Hurst Street and the Arcadian, over the weekend.
The "two strikes and you're out" method aims to stamp out the anti-social, threatening and abusive behaviour which plagues the city centre's nightlife. Police also believe it will reduce the fear of crime in the city.
Inspector Sean Russell, who is part of the entertainment team at West Midlands Police, said: "This new idea is a practical tool for tackling anti-social behaviour and preventing short-term re-offending. It has been well-received by officers and the public.
"Just about everybody understands the principle of being shown a yellow card as a warning and a red card for a repeat offence. It will make it clear to people that they have overstepped the line.
"Some people just get carried away when they are having a good time without thinking of the consequences of how their behaviour may affect others. They don't think about how they could be intimidating to others. We don't want to spoil things for people who want to have fun without alarming or distressing others, but we won't tolerate anti-social behaviour."
The first two yellow cards were handed out at 11pm on Friday to two young men for being drunk and disorderly. One of the men was subsequently arrested.
At the same time, officers went undercover to confirm that door staff at bars and nightclubs had identification and were properly registered.
They also checked fire exits were not blocked, businesses were not exceeding their entertainment licences and no-one was flyposting.