Where I am, and anywhere that the power company buys power back at a different rate to that which they sell it, smart meters are required, by definition - a spinning disc meter will do an approximation of net power use and associated billing in a tariff equity situation, but as @gordon pointed out they weren’t designed for that purpose. In my case a smart meter is required by law, and it would be fairly obvious you had an unapproved setup as accounts staying in credit when installing solar is very common - they’d be on it like a flash (but a safe, non-ionising, non-cancer causing flash).
Two points - peer reviewed scientific study reference please, and perhaps a new topic for this as it is a clearly separate issue to using a smart meter to save energy and/or money.
