Well, channel stuffing is illegal, so it's not called that. It's also nothing new. It's also not limited to the Auto industry.
That being said, pictures of lots full of new vehicles, don't prove anything, if we don't know the details.
I can say that back when I was a Business Owner, I was 'encouraged' to buy inventory of low-demand product, that I didn't want.
Yeah, I could've pushed the issue, and maybe even prevailed in a court of law. But in the meantime my Business would've gone in the toilet.
It doesn't matter if you seemingly have all the evidence on your side, going to Court is never a sure thing.
So you pick your battles.