Young people are being warned by police about trying to disguise alcohol in soft drink bottles at this year's Bath Music Festival.
Officers say they will clamp down on youths getting drunk and causing trouble at the event.
Patrols will be stepped up and mounted officers are being brought in during the run up to opening night on 20 May.
Insp Paul Mogg said "a range of tactics" will be used to stop drunken teenagers ruining the event for others.
"Traditionally there have been a minority of young people who bring alcohol to the opening night and in the past there have been occasions where we have had to deal with groups of drunk and abusive youths.
"We are well aware that young people try and disguise alcohol by camouflaging it in soft drink bottles and will be using a sophisticated device to check containers, he said."
He added that police had not ruled out another "sting" operation, similar to one last summer, which targeted licensees selling alcohol to underage people.