Name-brand perfumes can get away with this, because they can put the actual perfume in the paper, and WYSmellIWYG.  But for a beverage, they're either forced to put in a taste that's different from their product, or they're forced to admit just how fake and reproducible their flavor is.

Also, there's a long-term health issue.  Sure, you aren't going to be licking your People any time soon, but what happens in six months when it's still lying around, you've gotten over your cold, your dog's shed, and now your 4-year old niece is visiting and sees a lickable ad while looking through your stack?  Is it still going to be sanitary?

(is 3fingerspointback)

    The idea of "scratch and taste" seems kind of inevitable, considering the various marketing ploys already tried (on various scales) in the '50s: theater seats that vibrated or shocked some customers, small X-ray machines that showed the bones in your foot, "scratch and sniff" the first time, and doubtless a half-dozen others that I've never heard about. If it's technologically feasible, it seems an advertiser will try it once.
    But seriously-- grape juice? This seems like a move which has backers that want it to fail. If you have kids, you probably look at the juice aisle on most shopping trips, and as far as flavors go, grape is right up there with apple in the "hard to avoid" category. Everyone who wants an excuse not to taste a magazine will be able to use this as an excuse, and those who want a taste of Welch's will just go buy a bottle and get the real deal, not a chemical approximation.
    Now, if this were some unusual combination, something that may not be in every grocery store yet, I could see getting adventurous to find out if the innovation worked-- you'd get a sense of the novelty, without having to lay down even a buck for a small bottle, much less a pint, or gallon. "Grape and passionfruit? Sure, let me give that a free trial."
    Which is still possible later on, I guess, but it's hard to imagine advertisers getting too frisky if this ends up being even a mild failure, much less a New Coke level of notoriety. ("Later on VH-1's 00 Flashback: remember when Welch's thought it was a good idea to lick a magazine? What were they thinking?")
    Whatever the future is, let's hope the folks over at Dexter don't get any crazy ideas . . .

Ex ignorantia ad sapientiam; e luce ad tenebras

I was a fishing guide at a remote lodge on the BC coast for a few seasons, and as you can imagine there were a few porn mags floating around the bunkhouse.  One, in the early eighties, was a Hustler mag which had a fold-out featuring a "scratch-and-sniff" vagina of the featured model.

By the time I saw the magazine, there was hole in the page, right smack between her legs.  Apparently it was a popular, uh, diversion, but I can't speak to its olfactory accuracy.

Taste is mostly smell,  Thus, anything that tastes significantly is going to smell.  And a significant number people are going to refuse to buy any magazine which smells different, or will have an allergy to it.  To make money on anything like this, you have to do it very frequently, so that your revenue on this type of ad makes up for the small but significant fraction of customers you lose permanently.  But common sense wouldn't be "edgy".