Let's get the easy stuff out of the way first: The 46 (mostly teenage) people cited for public intoxication or alcohol possession at a rock concert at Wolf Trap last week may well deserve whatever book gets thrown at them. There's no note from Mom that excuses underage drinking, particularly when it involves driving, as getting to Wolf Trap invariably does.

There is, however, a very big "but" here. But: Don't blame the kids if they're shocked to find themselves in the dock. It may strike them that what had been acceptable (if equally illegal and antisocial) behavior at other concert venues suddenly became criminal when the party moved to Wolf Trap.

Is there something inconsistent about this? Would the same thing have happened at MCI Center, the Nissan Pavilion, Merriweather Post Pavilion or any other local concert venue? Or can the kids, guilty though they may be, legitimately claim confusion over what might be called situational venue ethics?

Anyone who has attended a rock concert knows that rowdy, and sometimes illegal, behavior occurs. The history of rock music can't be told without a side trip through a lurid catalogue of live-performance excess and even tragedy. The Hells Angels at Altamont. The Who stampede in Cincinnati. The second Woodstock show, which ended in fires, looting and allegations of rape.

In fact, the first Woodstock, despite its reputation for peace and love, was a mess of gate-crashing, drug-taking and general filth-wallowing. Contemporary innovations include the mosh pit and the rave, in which assault and chemical ingestion, respectively, have been raised to semi-acceptable forms of "self-expression."

But this is to use the extreme to define the typical. Most rock shows have been and continue to be peaceful, joyous, highly ritualized affairs. Over the years, rock fans and police officers have developed an implicit social contract: As long as behavior doesn't become obnoxious or overtly dangerous, the fans get a little slack from the law.

It's this kind of expectation that makes the Wolf Trap arrests so aberrant. It's unusual for a dozen people, let alone 46, to be busted at a local concert. The only show that comes close in recent years was the 2002 HFStival, a multi-band show at RFK Stadium. During that event, police made 38 drug-related arrests. But that was a concert attended by about 60,000 people over two days in searing daytime heat, in which 30 fans were hurt in a stampede in the mosh pit and another was seriously hurt in a fall from a pedestrian ramp.

Compare that with the Wolf Trap concert, which was attended by 7,000 on a pleasant evening.

Even more to the point, it's hard to make the case that the Wolf Trap crowd was especially prone to malfeasance. O.A.R., the rock/reggae band that was performing when the arrests occurred, is about as sunny and wholesome as rock gets. The group (whose name stands for "Of a Revolution") was founded by four buddies from Wootton High School in Rockville, and a fifth friend whom they met while attending Ohio State. The band has been known to stop playing if someone starts crowd-surfing, and its roadies have ejected people who are drunk or disorderly.

(Full disclosure: The mother of one of the band's co-founders was my son's kindergarten and first-grade teacher 13 years ago; my wife and teenage son attended and enjoyed this week's concert; neither one drank alcohol or was arrested, so far as I know.)

Yet Fairfax County police and Park Police at Wolf Trap clearly targeted the O.A.R. show for extra-heavy enforcement. According to an account of the arrests in Thursday's Washington Post, officials met in the spring and reviewed the park's performance schedule to determine which audiences might present the biggest "challenges," as park Director William Crockett told reporter Tom Jackman. O.A.R. attracts a generally younger crowd; ergo, the cops were waiting.

In other words, Wolf Trap and the local law set up a speed trap, daring the park's patrons to bring their worst on.

That some may have is unfortunate and maybe predictable. But let's review: Wolf Trap obviously knew what it was getting into when it decided to book a rock group in the first place. Perhaps it is now reconsidering whether a place known for symphonies, ballet and musical acts that appeal to a decidedly older crowd is the right venue for youthful rock concerts.

Enforcing the law is always to be applauded, but I'd feel a lot better if the same standards applied everywhere. As it is, the incident sends a mixed message to younger music fans. As a parent, I know I'd like to be right all the time. But short of that, I'm just hoping for the next best thing: that I'm consistent.

Rescuers tend to a person hurt at the 2002 HFStival, which had 38 drug arrests over two days. Last week's Wolf Trap event had 46 alcohol arrests.