I spent my professional life protecting ownership of images, through the Professional Photographers of America, our state professional association, and on our own. I was on a national committee that helped develop the PPA's stand on copyright protection. Yes, the usage of those images is not legal, although most private avenues to pursue damages aren't worth the effort. The "big guys" (like Wal-Mart, K-Mart, etc) have been sued and LOST copyright infringement cases. It actually became a source of revenue for our professional association (can't say I'm happy about that, either).
Here's my (definitely biased) take: "using" (insert "borrowing", "stealing", "referencing" or any other term you prefer) someone else's image without express permission (and posting an image here does NOT imply permission for others to take that image) is wrong. Someone that would do such a thing likely has no other ethics, and I would certainly recommend NOT DOING BUSINESS with these types. If they will steal an image, will they be honest in their other business dealings? If they're not fair in taking something that doesn't belong to them (to promote their business), will they be fair in pricing service work to their customers? It's easy to plead ignorance, when the plea should be something else.
The factory should provide images for their dealers, or the dealers should shoot or purchase images themselves. If they contact an owner and ask for permission BEFORE ANY USAGE, and get that permission, well that's a different story. Some folks would be proud that their images are being used that way.
It's an ugly can of worms, but stealing is stealing. If they were using my image without permission, I'd be making some demands... forcefully... and with the backing of my professional association and their drooling lawyers.
You can't copy an author's book. You can't duplicate a studio's movie. You can't "knock off a few copies" of a CD to give to friends. Unless it's "freeware", the software you use in your computer is copyrighted. Images are protected likewise.
Yes, people do it (steal images). Some people also shoplift. Or rob banks. The fact that they do it doesn't make it right. They are stealing someone else's intellectual/artistic property.
And in the words of the great philosopher Forrest Gump: and that's all I got to say about that.
Jim B.
M. Photog. Cr. CPP