is there a way to not allow them to enter anything except the value returned by Google?
Actually there are several options
use events
You can do as I did in the demo to show / hide the “green tick”. Here is how: create a workflow which enables the submit button when an address is selected from the list. In the demo, the event is “AddressInput select an address”. Also create a workflow to disable the submit button when the user writes an address instead of selecting it in the list. In the demo this event is “AddressInput type an address”.
Use states
You can use the AddressInput states in your workflows, to test if the user selected an address in the list (the AddressInput’s state “Selected address” is set) or typed to change the selected address (Selected address is empty)
