I wouldn't consider it rude at all. But I feel it would create awkwardness and frustration for the person who seeing their gift been returned. This is how i experienced majority responded automatically and naturally! Nothing personal.
People give gifts to each other in so many positive manners and purposes, and they get happy to see their gift brought pleasure and being useful. So when their gift been returned, they might feel frustrated about their choices.
There's two tips:
Tip 1: We need to generally learn to be careful about what we buy as a gift, when we buy without knowledge of someone's preference and needs, we need to be ready that our gifts might fall down from the priority into the receiver's life and they might return our gift at the end.
Tip 2: We shouldn't become sad or feel frustrated about our gift been returned. Because the most positive point would be, the receiver felt and seen we do care enough and we remembered them to buy something for them. If it didn't became useful enough. It's no one's fault. (which usually as i seen, most people don't think it that way! Frustrations comes a bit anyway!)
So according to what I experienced, i won't never take a chance to make someone feel frustrated or insecure about what the chosen. If what i receive as a gift don't be useful or nothing that i would like at all. I won't return the gift. The way i see it, it's a gift, i never request what i like for a gift, the best part about a gift is to be surprised so i never make a big deal. I would still collect all the gifts that i can't use them or i will donate them somewhere in need.
Note: Also some people become sad as they see their gift is not being used after they visit or ask about it ! Which i would consider it a wrong expectation. We give gifts but what they do with our gift is not our business anymore. It's theirs from the moment they receive it.