Should the caller of PackagePart.GetStream dispose the returned Stream object? Or does this method return an object that could be reused? The documentation doesn't say.
Looking at the .NET source code, almost every place calling GetStream() disposes the result, either directly or indirectly. My best guess at an answer is that the result of GetStream() can always be disposed, but doesn't necessarily have to be if the parent PackagePart is disposed.