They may look carefree, but they are here on a mission. Infiltrating. Blending in. Bent on destroying the very fabric of American life. Terrorists? Nope. Tourists. Fake ones, that is, unleashed by Sony Ericsson. You'll find them at the country's top sightseeing stops, looking dorky and asking strangers to please take their picture.

Do they really want a snapshot of themselves? Not at all. Do they want us to try the new Sony T68i camera/cell phone? You bet. And that's the whole point. They're shills. Welcome to the brave new world of covert marketing.

"Fake tourists and 'leaners' are just part of a bigger campaign," explains Nicki Csellak-Claeys, head of strategic marketing for North American Sony Ericsson.

Leaners?

Apparently leaners have been around for at least a decade: Attractive people paid by a company to "lean" into the crowd at a bar and order a particular product. "Don't you love the new vodka, X?" a leaner will enthuse. "It's triple-filtered so you don't get a hangover. Bartender! How about a round of triple-filtered X for my new friends?"

Sony's leaners will be puttering with the camera/phone in popular bars, chatting it up with anyone duped by their pre-paid, professionally scripted, fake-as-silicone spontaneity. To desperate corporations, this seems like a great idea.

Who cares if it means we can't trust any human interactions anymore?

"This is what I call 'reality' stuff," says John Palumbo, president of DVC Experimental Marketing, a New York firm specializing in covert campaigns.

By "reality" Palumbo means using real people to create unreal situations. For instance, he hires groups of real friends to go into a restaurant, order a certain liquor and keep the bottle on the table all night, as a visual ad.

He has also hired people to whip out a particular electronic device on public transportation, to make it look popular. In Chicago, he paid a bunch of people to ride the trains, pretending to read a new magazine. And when he was hired by a catalog company he came up with his cleverest idea yet:

He took the company's boxes to doormen all over New York and paid them 10 bucks each to keep a box in plain view, as if a resident had ordered an item from the catalog and had yet to pick it up.

"It reinforced the idea that, 'People in my building are buying from that place'", says Palumbo.

Even though they weren't.

"It is impossible to be too cyncial about marketing right now," concedes Scott Donaton, editor of Advertising Age. Between channel surfing, ad clutter and new technologies that edit out TV spots, "Marketers are afraid traditional media advertising is not going to be as effective as it's been. So they're looking at sneak attacks and pretending something is grass-roots. Everything is marketing."