In my opinion you make a "leap of logic" (not the same as a logical leap) that these are ordered. Bottom line is that if Java supported better multi-value initializers (like Groovy, etc) I would have opted for that for passing in the values. Really the incoming ids are more treated as a Set. But again Java does not have a nice syntax for creating and initializing a Set of values.

I also really dislike this argument that because the documentation does not say specifically that any individual interpretation is right or wrong. The documentation also does not say that every other return element will be some random object; does that mean we should either do that or document it?

I could see an argument for allowing such behavior as an enhancement. But that would be an enhancement, not a bug. By definition, something has to work in a way other than designed in order for it to be properly considered a bug.