It’s not a lease program. It’s not a rental. There’s no financing, down payment, mileage limits, or long-term commitment involved. Rather, it’s an innovative monthly subscription-based upscale car sharing program from Cadillac that could well be the proverbial shot heard ’round the world in the revolution that threatens to redefine the concept of auto ownership. It also makes more traditional car-sharing services like ZipCar and Car2Go seem cheap and paltry by comparison.