Sulu laughed. "Just make sure to put some kind of copyright somewhere, so everyone knows you're the genius behind it. So," he looked from Ianto to the Plass, considering the people around them. "What happens when you leave the social-invisibility shield this thing has? Does anyone ever stop to say 'I didn't notice you there a second ago,' or is it just a matter of everyone keeping to themselves?" He knew that in San Fransisco, at least in his time, you'd get stopped pretty fast by someone. Probably a cadet on the physics track.