If you're an underage college student in La Crosse, Wis., you might want to make sure the pretty girl that just sent you that Facebook friend request actually exists. Police there created a fictional online persona named Jenny Anderson in order to root out underage drinkers from the University of Wisconsin-La Crosse.

Police used the profile to search for posted pictures of students holding drinks at parties, then called them down to the station and issued citations for underage drinking.

The officer behind the sting, Alan Iverson (probably not the famous one, though Shaq and Steven Seagal are sheriff's deputies, so who knows?), told the La Crosse Tribune that using Facebook and social networking sites in this way "has to happen -- it is a necessity." Which kind of set off our BS detectors ...

The fact that police could theoretically track child molesters on Facebook doesn't automatically mean that using it to check up on underage kids drinking at a party is justified. But even setting aside the ethical dilemma here, is this even legal?

"I guess so," Dal Ruggles, an attorney at the criminal defense law firm Sumpter & Gonzalez, told Asylum. "It's not really entrapment. It's just a lazy and opportunistic way to take advantage of kids' recklessness." If it happens again, though, Ruggles said that he would advise students just not to go down to the station.

"Police ask people to come in and meet all the time. They can say no," he says. "I'm not sure how far the police would take it, but it's just an investigation at that point." And if it did go further -- say, to a trial (however unlikely) -- he'd eschew the Chewbacca defense for something more straightforward. "Prove that it's alcohol in the picture. Prove that the kid is drinking it."

We're hoping the streets of La Crosse are pretty effin' safe at night if the police have time to sit around on Facebook doing stuff like this. Oops, hang on -- this random hot chick just sent us a friend request ...