Error
I created a defined value for cities for filtering with the core group finder block. I enabled adding new items so that group managers can add new cities when they create groups instead of going to defined types to add another value. The core group finder block includes the Add Item button in the filters for end users to use. I suggest removing this ability so that filters work as view only.
This is not possible with the field type. The add button either displays or it does not. There's not way to change it based on context.
Cultivate your ideas for maximum impact with these helpful submission tips that will increase the chances of your brilliant concepts becoming reality.