We’ve encoun­tered some dif­fi­cul­ty on set with the smart­phones. They’re not real­ly props, they’re real things. For exam­ple, it’s hard to hide the date and time, or the car­ri­er on the dis­play. If you have a movie with­out an AT&T agree­ment, you can’t show the AT&T logo on the phone. It’s very tough to remove that with­out VFX dur­ing post-pro­duc­tion. We have to write pro­pri­etary apps most of the time. It’s a real device but it’s been co-opt­ed by us. It still has all the inter­ac­tive func­tions the phone has but we can con­trol what is dis­played and when. Addi­tion­al­ly, we can start mak­ing it do things a phone nev­er does. That’s the FUI/FUX part.”

Tim­o­thy Peel designs fake UIs for your favorite films, and talks about it here.