Lucky for him, he wasn't selling loosies.

Martese Johnson, a double major at the University of Virginia and a member of the school's honor committee, got turned away from a bar last week. Johnson was not trying to use a fake ID; Trinity Irish Pub in Charlottesville was turning people away because of crowding. Still, agents from the Department of Alcoholic Beverage Control pulled him aside—and the next thing anyone knew, Johnson was lying on the ground, bleeding from the head.

The story went national in hours, and has revived the sensible suggestion that the State Police take over the ABC's enforcement duties. No wonder: This isn't the first time the ABC has embarrassed itself. Two years ago it made national headlines when plainclothes agents suspected another underage-drinking offense. The agents saw U.Va. student Elizabeth Daly and a friend leaving a grocery store with something that might have been beer. The agents later learned it was water. But that was after they terrorized the two young women by swarming their vehicle, trying to bash the window in with a flashlight and drawing a gun.

Daly spent the night in jail on three felony charges. She sued, won, and eventually got more than $200,000. Yet the ABC's first review of the incident absolved the agents involved of any wrongdoing. After sustained public outrage and another investigation, it said the agents involved had violated policy. The ABC announced some minor changes, such as requiring enforcement personnel to wear outer garments identifying them as ABC special agents. But it ignored larger issues—such as whether paying a half-dozen agents to skulk around a grocery-store parking lot to nab kids buying beer constitutes a reasonable use of public dollars. And whether underage booze purchases are serious enough to warrant a violent response.

While "we cannot undo" what happened, said ABC Board chairman J. Neal Insley at the time, "we can only do our best to learn the lessons from this experience." Judging from Martese Johnson's bloody face, some in the agency haven't learned enough.

Recent episodes—the Michael Brown shooting in Ferguson, the Rolling Stone story on U.Va.—offer the reminder that jumping to conclusions is dangerous. Initial reports often need later revision. So the investigation Gov. Terry McAuliffe has ordered into Johnson's arrest is a welcome step. It's important to get all the facts straight.

Yet in the past few days nobody, including the ABC, has accused Johnson of being physically aggressive in any way. In fact, the owner of Trinity Irish Pub says Johnson was "cordial and respectful." Nor was New York's Eric Garner being physically aggressive when he was strangled by officers arresting him for selling individual cigarettes—"loosies"—on the street. Garner ended up dead anyway.

Garner died in the midst of an NYPD crackdown on "quality of life" issues, among them the unregulated selling of smokes. Concern over petty crime dovetails with the emphasis on "broken windows" policing, which holds that ignoring small crimes creates an environment conducive to more serious offenses. That's certainly plausible.

But it's also plausible that the increasing regulation of just about everything creates more opportunities for potentially violent citizen encounters with law enforcement. Half a century ago only 5 percent of the workforce needed a government license. Now nearly one in three workers do. Combine that with the militarization of the police and you get a situation like the one in Florida five years ago, when a SWAT team raided barbershops and arrested three dozen people, primarily for barbering without a license.

Regarding cigarettes, there's another issue public officials usually don't mention: revenue. New York's combined state ($4.35) and city ($1.50) levies create a huge incentive to smuggle cigarettes in from other states, such as Virginia—where the cigarette tax is only $1.68 per pack. By one estimate, cigarette trafficking costs New York $600 million in revenue per year. No wonder the city is cracking down. If you're going to sell drugs in America, you need to make sure the government gets its cut of the profit.

Profit also is the principal reason Virginia maintains a state monopoly on the sale of hard liquor. When Gov. Bob McDonnell proposed privatizing the state's package stores, legislators objected primarily on the grounds that doing so might cut into the budget. Whether citizens might benefit rated as a secondary concern.

Some of those who fought McDonnell's privatization plan did so for moral reasons: They worried wider availability would lead to more drunkenness in general, and more alcohol abuse by the young in particular. The latter concern, obviously, is what drove the takedown of Martese Johnson, and you can certainly understand it. After all: We don't want anybody getting hurt, now do we?