Effy, An LLC is NOT a business. I repeat, it is NOT a business. An LLC is an asset protection tool regarding lawsuits not a business. People who put their personal residence into an LLC are not evading or avoiding taxes. They are protecting themselves from lawsuits. Their house isn't a business, but if someone gets hurt on their property they want to protect their other assets. How can that even remotely be illegal?
You are confusing the terms. An LLC can be setup by anyone and LEGALLY be used to not pay sales tax if they are in compliance with the laws of their resident state. For example, I could buy an RV and use a Montana LLC to license it and do so legally by not bringing the RV back into NY State. I would be in compliance with the laws of my state, NY, and in compliance with the laws of Montana so how does that become an illegal activity? If someone is in compliance with the laws of their state and they can document that compliance then there is no crime.