If you have a car that and it's making sqeaking noises and warranty can cover it, by all means BRING IT IN. And it honestly would not be that hard to figure out what it is. If the noise is in-fact coming from inside the door panel, then they would take the panel off and feel around until they found it, which would probably take all of 5 minutes to do. It's probably just something that got a little loose, and they may use felt lining or something of the sort. So I don't mean to make fun of anyone on HAN but I think the "engineered squeeks" story was the 2nd stupidest thing I've ever seen on this forum, no joke.
So yeah, dude, I say bring it in and at least have it looked at.