Well the copyright laws state that one may not use a Registered Trademark for profit, without written permission. For personal, non-profit use not a problem. Like my Bedslide, I have the Bow-Tie on it. If I were to sell the slide I'd have to take off the Bow-Tie. If in doubt, don't do it with out their lawyers input.
There is also what's called a generic name. Like the word Jell-O, it has been used so often that it is used to describe any desert that "wiggles and jiggles" (Trademark of Jell-O not used with permission) made with gelatin. Also did you know that Aspirin, Linoleum, Nylon, Escalator, Kerosene, and Zipper used to be all Name Brands?
I hope I've helped. I probably added more to the confusion though. I would ask the Lawyers first.