I just tried to set up a second EA account so I could charge the ID4 for free same as my wife. When I tried to get the activation code though VW said they allow only 1 EA account per car. I assumed the chargers would recognize the car as eligible for free charging, but it sounds more like it recognizes the account. So my question is, does this mean one could charge other EVs besides the VW using an account with the free charging? I don't have another EV, just a small-battery PHEV Honda, but I'm curious.
At the moment you need to share credentials. Once plug and charge is enabled, I presume you won't even need your phone to start charging.
I share my wife's EA account credentials and have an EA account in my iPhone's Wallet app. This account is tied to our specific ID.4. If you tried to connect another vehicle to this account I do not believe that EA will enable the charge, although, truthfully, I have never tried this.