|Tasty. Tasty. Very, very tasty|
Well, I work in a shop that has, shall we say, a large selection of highly-priced alcoholic beverages. And yes, we do tasters of selected products frequently. "But that's giving stuff away!" you're saying "How will you make any money on it?". There are several things to consider.
Often, we are given a bottle of whatever by the producer or distributor to use for this very purpose. It costs us nothing and the producer very little (they knock them out at cost, and presumably write it off against tax). Do brewers of craft beers give a small "promotional" discount to pubs for pushing tasters on customers? I'm not sure, but it's not beyond the realms of possibility.
Another thing to consider is that People Like Free Stuff. Yes, there are piss-takers. You get to know them well as by definition they keep coming back for more. We serve them with a smile and a chat nonetheless. It's not worth destroying goodwill for a few thimblefulls of beer, wine or whisky. A sip and a chat make people feel good, and even if they don't buy what you're offerering them, perhaps they'll buy something else while they happen to be in the shop.
The best thing you can do with tasters, counter-intuitive it may seem, is to get the customer to try as many as you have available. In my experience, very few people have the absolute brass neck to try four things and not buy at least one. Maybe they genuinely adore whatever they take away, but you'd be surprised at how many people feel obligated to purchase after you've given your largesse to them. And this is how tasting really works.
Think about it. Many companies have cut sales staff and representatives and even advertising. If they weren't making any money out of tasting, do you think they would bother doing it? It costs buttons as opposed to so-called "real" promotions. They don't even have to employ anyone to do it - the end seller provides the staff, glasses and time.
I doubt tasters contribute in any real sense to the phenomenon of the £6 half of Imperial IPA. No, that's probably more down to fashion, and the good old capitalistic principle of charging as much as you can get for things. Tasters, in the majority of cases, work and are actually good business practice.
A taster of beer isn't enough for me to get the gist of the drink, but if they make people happy and promote the product, then isn't that worth a few pence on your pint of Craft?