Earlier this spring, the folks at WTVD-TV, the local ABC affiliate in Durham, N.C., had a bright idea. To drum up interest in the station — and raise its profile on Facebook, Twitter and Google Buzz — it organized a sweepstakes contest and gave 11 lucky winners the hottest prize in consumer electronics: an Apple (AAPL) iPad.

What the contest organizers didn’t realize — but would have quickly learned if they’d done their due diligence — was that they’d just run afoul of Apple’s Guidelines for Third Party Promotions. Operating on the theory that its brand is one of its most valuable properties, Apple has laid out some pretty strict rules about what companies can and can’t do with its products. Among them:  (I quote)

• iPad, iPhone and the iPhone Gift Card may not be used in third-party promotions.
• iPod touch is only allowed to be used in special circumstances and requires a minimum purchase of 250 units.
• You may NOT use the Myriad Set font on or in connection with web sites, products, packaging, manuals, or promotional/advertising materials.
• The use of “free” as a modifier in any Apple product reference in a prominent manner (headlines, call- outs, etc.) is prohibited.
• You must submit all marketing materials related to the promotion of Apple products to Apple for review.

The two-page document that lists these guidelines — and many more — has been around at least since January, but it seems that Apple has begun reaching out to companies to enforce them only recently. Earlier this year, Cult of Mac’s Nicole Martinelli counted more than three dozen active iPad sweepstakes and giveaways, including contests run by Mashable, MacMall and Mahalo. None of them, as far as she knows, was ever told not to do it.

Apple declined to comment.