I like your thinking. If you search past enforcement cases, it has happened where the higher experienced, cetificated airman was violated, even though they was not acting as the "PIC" by whatever verbal agreement was made between the parties.
Definitely have Aviation Renter's insurance, AOPA Legal Plan, and an "umbrella policy" on top of your personal homeowner's insurance is not a bad idea either.
You could look into professional liability insurance if "freelance instructing" and/or setting up an LLC for your pilot services. Seeking good legal advice from an experienced aviation attorney like "Yoda2" is also advised.