If you are a smal ldeveloper it is a bit of a grey-zone. For example in 3D vsualizations you see a lot of cars from common brands. In theory every artist would have to ask for permission or use fantasy cars. This would not be accepted by cliets. So everyone uses cars from those brands.
So I guess as long as noone can be killed with your virtual iphone as a melee attack weapon noone will sue you. ;-)