Just took a ride down to Santa Clara this past weekend to check out their new flagship station. Our "gas" station of the future. What was amazing was how quiet the cable cooling was. the station was almost full (14 stalls in operation) and I need to verify that I was actually charging.
I too have a Juicebox and I found the best situation is to let the Juicebox manage the charge and not the car. Basically I set the general profile to charge to 100% on the car and set the max on the JB to 85%. The only drawback is that you need to tell the JB the current SOC when you plug in.
Just to add, I just ran into this very issue for the first time yesterday (charge cable wouldn't release). I ended up calling Electrify America and even after a station reboot I was still locked in. He had me try a tick that works for the ID4 and that was to hit the unlock button on the remote 3...