Yes, Plugshare is THE app for charging stations. BTW, I went all through SoCal and added every Ford dealer to the Plugshare lcoations. I went conservative and restricted it to only Ford vehicles, so they are all grey in the map locations. (I didn't want to be presumptuous and expect Ford to let everyone charge there.)
But, Ford dealers are REQUIRED to allow charging at their locations in order to be certified as electric vehicle dealers. As published in the official Ford publication, @Ford Online, dealers must meet a list of requirements to become certified, including:
• One of the two required charging stations at the dealership must be in the customer area and the other must be in the service area.
I think it is fair to read this to mean that the customer area station is for the use of customers and Ford owners. So, if a dealer refuses to allow you to plug-in, read him the requirements and ask him whether s/he wants to call Ford to see if the dealer should remain certified, or should you.