My cars are never locked in the garage. For decades, in Maine, the garage was unlocked and the cars usually had the keys in them. My house in Maine didn't actually come with keys - I never had any until I changed all the knobs to handles, keyed alike. Florida, not so much, but I still don't lock the car when it is in the garage.
And no, whether locked or not makes no difference in power drain. These cars will go dead in a few weeks either way.
