I’m afraid you misunderstood my point. As to whether or not assets must be covered under GPL license, please read my previous post.
To reiterate, I tend to see it as you do although I acknowledge that it’s something lies in the gray area. But as I mentioned in that post, I’m happy to understand that assets can be released under a non-GPL license as long as the Blender people interprete it that way.
On a side note, it’s still quite a restriction even with such a method since it’s often the case that you need some type of scripts attached to those assets to drive them. And it’d be quite a hassle (I’m not sure if it’s possible at all) to keep every scripts in a single .blend file, for example, to circumvent the license.
Ideally, users should separate their games to organise the contents in levels or assets (e.g. characters, items, etc.) rather than being forced to split them according to license types.
P.S.: It just came to my mind: Maybe we should take the opposite approach if we are to circumvent the license restriction that way? I mean, why we should split .blend files when we can just externalise all Python scripts and release all .blend files under a non-GPL license?
I still see the Blender’s interpretation of GPL to be questionable (but I won’t contest it as it’d be shooting myself in the foot). But as we established that assets can be covered under a non-GPL license, maybe it’d be a better approach to keep all scripts in external files rather than trying to separate non-scripted and scripted .blend files.
The bottom line is, we really need to reach a consensus on this matter and give a clear instruction to our users to circumvent the restriction. Currently, even the official manual contains inaccurate information and sometimes UPBGE developers/contributors don’t agree with each other.