I know what you mean actually... my power support was applied in the apple store and was completely dust free. Now, three weeks later, it looks like there are two pieces of dust in different areas. However, I don't think it is dust, rather, I believe they are scratches (on the film). It is physically impossible for dust to get under the screen.
I haven't felt like removing the film just to prove it, but that is my theory.
It sounds like others have been getting new phones based on dust under the glass... but it also sounds like this occurs or will occur on every iPhone. Mine has some dust as well (that I am pretty sure was not there when I first bought it). I am going to hold off on replacing my phone because Apple needs to fix the design/process to seal the screens tighter or this will happen on any replacement phone too.
I had some dust under mine. What I did was apply scotch tape to the static side and that removed most of the dust. There will be creases on the plastic but they will work out and be gone. Whatever little bits of dust that were underneath it seemed to have moved out from under it.
I have what appears to be dust under my PS Crystal too but been kind of scared to take it off to see if it's under the glass. Once off,I think the PS film is going to be worthless. I botched putting on the first one so I don't have another. I was thinking l'd take it off towards the end of the warrenty period and if it's under the glass then I'd turn it in. Hopefully by that time they'll have out a few manufactuing issues.