Abercrombie & Fitch's (NYSE:ANF) sexy brand and smoldering models have helped the company get where it is today, but apparently it's OK only to be irreverent on its terms. The retailer was recently the subject of an Improv Everywhere prank, which sent a group of 111 shirtless men into Abercrombie's Fifth Avenue store on Oct. 13.

The store's management staff and security ended up driving out the offenders, even though it looked as though many customers found it amusing. And how's this for irony? Several of the shirtless men were turned away from trying to buy $45 shirts. (They clearly needed them.) Meanwhile, this same Abercrombie store happens to have a live, shirtless male model greeting customers, as well as a bronze statue of -- you guessed it -- a shirtless man.

Improv Everywhere has pranked many big-name corporations over the years. It sent a crowd wearing blue shirts and brown khakis into Best Buy (NYSE:BBY), and it didn't spare big-box retailer Home Depot (NYSE:HD), where pranksters shopped in slow motion and then eventually froze in place. A couple of Starbucks (NASDAQ:SBUX) stores found themselves in the midst of a "moebius," a Star Trek-inspired prank in which the same five-minute events repeated in a time loop for 12 repetitions. And the troupe also installed a tuxedoed "bathroom attendant" in a McDonald's (NYSE:MCD) restroom.

I write for an investing website, so should I really think it's funny? Well, sure ... because it is. This is the type of homegrown entertainment that makes it big on social-networking sites such as Google's (NASDAQ:GOOG) YouTube, and these pranks seem to be in the spirit of good fun. They also seem to delight customers.

Of all the companies I've mentioned, you'd think Abercrombie would take it the best, since it's aimed at a youthful demographic and has gotten into hot water for its own controversial irreverence at times. However, maybe some of the managers of its stores take the Abercrombie brand a little too seriously. Although maybe we can't blame store-level managers too much for their judgment call, it reminds me a little of Coca-Cola's (NYSE:KO) blunder, when it pooh-poohed the free viral marketing it received when people were making 20-foot geysers by mixing Diet Coke with Mentos.  

Sure, brands are serious parts of business, and they ought to be protected. But then again, some companies may want to remind their employees that taking brands too seriously might be worse than -- at least in some cases -- letting the good times roll.