If your model is not a replication of a real one, then there obviously is no issue. Copying a real one without using a logo is still illegal; the IP of the original is owned by the entity that developed it (or commissioned it).
Companies use dubious sources all the time. Still doesn't make it legal.
That link even states that copyright claim is dubious. It also only applies within France and selected other countries that have decided to uphold that ruling - like I said, the legal system is often irrational and illogical. In either case it's an exception to the general rule.
Yes, people have been sued for it. Moreover there are many modding teams that have had cease and desist orders brought against them for using copyrighted work. IIRC Enduracers had that from Porsche for their Porsche Cup mod several years ago. The first time I recall seeing it was way back in the SCGT days when a modder was working on the Tommy Bahama Qvale Mangusta Trans-Am car. He received a cease and desist from Tommy Bahama themselves for that one. Using content you do not own, without permission from the rights holder, is not legal. Period.
If a game developer has the rights to use a certain car in a game and they commission another modeller to make said car, the transaction is perfectly legal. If they buy a ready-made model that was created and sold by someone without a license it's still illegal - but no one cares, most likely. Again, just because something is done doesn't mean it's legal. It's the rights holder's responsibility to initiate action on these matters.
Straw-man argument. A driver's license is issued by a government to allow you to legally drive on a road. That has nothing to do with the source of the vehicle you use. A stolen car is a stolen car.
Making a model of your own design is obviously legal. Replicating a real car is technically illegal, but no one is going to care if it stays private. Selling that, without the license to it, is illegal but you'll probably get away with it, but you may not. Doesn't change the fact that it is still illegal. Replicating a real vehicle and simply not putting a badge on it doesn't make it legal - I know a lot of people in the modding community think it does, but it doesn't. The core design is still from a real vehicle and covered by IP law. The degree to which it must differ from the real thing to be considered legal is a grey area; it depends heavily on each sides' legal team and the one who is ruling over the case; it's very subjective.
Yes, cases do exist. When it comes to modding teams I haven't heard of anything ever going to court, but I've heard of numerous cease and desist actions.
You can argue all you want, too. Doesn't change the law.
No, actually, it's not a crime. It's a civil action, if I remember correctly. Breaking a law only makes you a criminal if it's criminal law. IP and copyright law aren't criminal laws. Hence the necessity for the rights holder to initiate legal action - the police aren't going to knock down your door for copyright infringement.
