It goes directly against the American Society of Magazine Editors’ (ASME) guidelines, but that didn’t stop Time Magazine from introducing a microscopic new type of ad last week.

It’s in a place you’d never expect it to be—the cover. And a sister publication, Sports Illustrated, is about to follow suit. More details:

About the ads: The two Time, Inc., publications, among the industry’s most storied titles, are running sliver-sized ads for Verizon right next to either the barcode (in the case of newsstand copies) or the mailing label (for subscription copies). It’s a starting point, however: According to Ad Age, the company is reportedly pitching slightly larger ads that run across the bottom of the cover. It’s part of a recent trend of magazine giants experimenting with the advertising form, and they’re not the first to test such a format. In 2009, Scholastic Parent & Child published an ad for a company called Smilebox on the corner of its cover.

Butting against guidelines: However small, Time’s experiment  flies in the face of the top rule in ASME’s print guidelines: “The cover is the editor and publisher’s brand statement. Advertisements should not be printed directly on the cover or spine,” the rule states. The guidelines list a number of other no-nos, including the use of ads that imitate editorial content. Violating the guidelines can lead to public sanctions or even disqualification from industry awards. Unsurprisingly, Time’s move drew a wide array of industry reaction.

A topic worth discussing: But due to the sheer size of the publications trying the new format—both magazines have a circulation topping 3 million copies, according to the Alliance for Audited Media—the move raises new questions for ASME, especially considering that one of its newest board members is Norman Pearlstine, chief content officer of Time, Inc. He argued to Ad Age that even if the ads flout the guidelines, they still are within the spirit of ASME’s four basic principles: “Every reader is entitled to fair and accurate news and information; the value of magazines to advertisers depends on reader trust; the difference between editorial content and marketing messages must be transparent; editorial integrity must not be compromised by advertiser influence.” Pearlstine told Ad Age, “If we’re not at variance with the principles, then it’s worth having a discussion of whether the [ASME] guidelines are relevant and still appropriate.”

For its part, ASME is ready for a bigger conversation. The group’s CEO, Sid Holt, was given a pass at the new ad formats before they went live, and while he noted to the Wall Street Journal that industry consensus is that such ads are “thought to lessen the effectiveness of the cover as both a journalism and marketing tool,” the Time and Sports Illustrated ads are likely to keep the issue front-of-mind.

“This will be something I’m sure the board and other ASME members will want to look at more closely in the coming months,” Holt told Ad Age.

A Verizon cover ad, shown on the latest issue of Time Magazine.