First off, those who are going to do a VIN swap are not coming onto a forum to try and get support, they are just going to do it. In fact there are a few very high dollar cars out there that are suspected of exactly this activity. When there are hundreds of thousands if not millions of dollars involved someone is going to try and cash in. If people can counterfeit $100 bills they can do a car to include the tags and stampings.
So to the actual question at hand, is VIN swapping illegal? Yes according to the federal government. Is VIN swapping unethical or immoral? I would say this is much more of a complicated issue but on the face yes however I do believe that there are situations where it might be a necessity. Typically when this subject comes up, everyone automatically things Hemi or 6 pack cars (or something equally rare and valuable), however consider this hypothetical situation;
You have 2 vehicles;
1. one is a run of the mill 383 (or even 318) 68 Charger (using this because of how desirable they all seem to be nowadays) but it is really rusty, like no frames, floors, etc. but it does have a good drive train, dash, seats, etc. You have a clean title and all the numbers are there.
2. the other car is solid but missing the dash (VIN plate) because it was a parts car. It too was a basic car but everything is rust free and usable, no collision damage or anything. You do not have a title for this car because it was a parts car but you do have a bill of sale and it is legitimately your car.
So, let's just say that it isnt an option in your state get a state issued VIN from your local Hwy Patrol/DMV. So you have 2 cars that are yours, both cars could in fact make one good one but you would have to swap the VIN. Now I know the hardcore guys will scream immediately that this is wrong, you should burn in hell, etc. but I don't think it is as simple as that.