OK, just one of the modders' opinion,
I don't agree a lot on Ripping content (especially) but there are still gray areas on this.
Actually I was using the EA model as a blueprint reference in my GT3R model(13' bodykit not pre-'12 bodykit, i.e. exterior can only be make from scratch) as there was no GT3R 2013 blueprint and has to make it on my own. I use that model just to make sure the dimension of parts are right.
The same applied to interior, I might consider that EA model in until someone can finish the interior suitable for the AC.
I agree on this, if you use existing model as a reference mesh but do not directly copy it, it's yours. The line on that is very grey as there is no way in hell to anyone to claim it wasn't modeled by you, since it was. But in any case, even then you can't use direct snapping to vertices as those can be interpreted as unique. And there is a lot of open material what to use, no one actually have to rip from existing licensed content. If the situation was different and even shaping with reference wouldn't be possible, i might think different. But since it is possible and it's not even that hard, lots of hours of repetitive shaping, direct ripping is a no no. Sometimes models we want don't have accurate blueprints available but you can find something really close already shaped, just model a new one basing that model as a reference.
If lower poly model was used as a reference, even better, IMHO. Increases the amount of decision when it comes to shaping, you need to use totally your own curves anyway. Direct vertice to vertice copy, even if done manually, one by one, is not good enough transformation, it's still a copy, a conversion. Then is texturing, using your own textures instead of ripping them too etc.. After all that, there is no arguments whose model it is.
Getting around identical data on 3D meshes is easy, some finely calculated scaling back and forth may create enough noise that the coordinates change locations but that is also cheating. And simple humanbrain will judge it as copy also when directly compared so.. Low poly to high poly manually and we are so far in the artistic freedom and methods minefield that it doesn't matter anymore..
I think it can be compared to a painting, if you use existing one as a reference, at which point it becomes yours and what technics would you allow. Photocopying? Draw-thru? If person has honor, respect and enough balls, that comparison is pretty easy to figure out.. And in the final case, you can always buy models very very cheaply that you can use where-ever, how ever you want.. That's something i only recently have learned, to make something (modding, game creation..) you can buy pretty much any parts for it and use your compiling skills to stitch them together.. You can go so far that you don't do actual modelling at all but modifying existing meshes is still pretty much required.. So if you really want to help the community as a whole, you can..