No, it's not necessarily a bad sign indicating something broken or something like that. Yes, something might be not completely perfect, but it doesn't mean it's actually bad. There are certainly cases where it is more on the side of actually being bad, but then there are just cases where it's simply not perfect.But generally, if we talk about technology and a certain device rattles, it is considered a bad sign. (Something must have been broken or is loose) Look at the 6S that feels and sounds rocksolid, it means it has properly been manufactured and will serve you well a long time. That's why some of us are concerned with these rattling buttons.