Instead of paying the cost to add a ground wire to a circuit, you can instead add GFCI outlets or circuit breakers to bring it up to code.
The Ground Fault outlets or circuit breakers measure the current flowing through the black wire and the white wire, if they do not equal each other then that means current is flowing through something else and it trips the circuit. This makes a two wire circuit very safe to use and this is allowed by code.
Adding a green ground wire is a great idea in theory, but practice is that it involves ripping out drywall and boring through walls. Unless your house has an open area underneath and/or above it with easy to access wiring, it can be very expensive to add ground wires. But in a house with a concrete slab and cathedral ceilings there is no access to anything.
The EVSE way of "protecting" you is by not allowing you charge without a ground. I think that is a little overkill...
PS: you only need the first outlet in the "chain" of outlets to be a GFCI, it provides protection to all subsequent outlets if properly wired.
Original 2011 Leaf SV #857 - Total Loss on 11/27/2015
New 2016 Leaf SL #300864