Does the owner of the getaway car get charged if they make it available for anybody to use for free as long as they provide an email address, no questions asked?
I certainly hope not. That sounds like an act of charity that's good for society at large. "People can use my car for free" is a good thing, even if someone might use it for a crime. Most of the uses of cars are not crimes and most of the consequences of letting people use your car for free are net positives for society.
If you have a free public transit system, some criminals might use it, but most of the people riding it will be law abiding citizens trying to get around. If you have a network of free cars, the same will be true.