One of the macro issues in the Ms. Magazine case was whether or not a publication endorses a product by running an ad and if the publication should be held responsible for claime of an ad. I've been thinking a lot about this, and I've decided that as long as the line between advertising and stories is clear, the magazine shouldn't be held responsible.
It drives me crazy when I pick up a magazine and start reading something I think is a story and then find out that it was an advertisement. I think this falls into the equity issue of the tares test. If something is an ad it should look like an ad, so readers aren't assuming it's an objective view.
Most advertisements, however, are fairly noticable. most people realize that the company is promoting itself. Although I think the magazine can print whatever ads they want, most people realize that the magazine isn't promoting a product, the company is promoting the product. The claims made in ads are the claims of the advertisers, not the claims of the magazine.