The Dark Knight, when Batman and Lucius were in Tokyo....?

Question

Lucius handed the security people his mobile phone but was allowed to keep another device that looked very similar to the phone. What was this and why was he allowed to keep it?

Answer 1

He wasn't allowed to keep it he smuggled  it in....

Answer 2

he brought two mobile phones with him because he knew he would have to hand one in. Security just assumed he would only have the one phone, and didn't bother to search him, so he got away with bringing the other one in. The one he gave in was able to send sonar images to the phone he kept. The sonar images hepled batman to break into the building to capture the asian man without getting caught, because lucius was able to see who was in the building.

edit: if security had seen his other phone they would have taken it away from him.

if you remember, when Fox was with lau, he recieved a message, and when lau says phones are not allowed, fox says "sorry. forgot i had it"

Answer 3

POSTED ABOVE:he brought two mobile phones with him because he knew he would have to hand one in. Security just assumed he would only have the one phone, and didn't bother to search him, so he got away with bringing the other one in. The one he gave in was able to send sonar images to the phone he kept. The sonar images hepled batman to break into the building to capture the asian man without getting caught, because lucius was able to see who was in the building.

edit: if security had seen his other phone they would have taken it away from him.

if you remember, when Fox was with lau, he recieved a message, and when lau says phones are not allowed, fox says "sorry. forgot i had it"

MY POST:

Just to add to what she said (since she's correct), when he's walking out, the guard says something along the lines of "Sir, your phone" and goes to hand Fox the phone he had originally turned in. Fox holds up his other phone as if saying, "Nope, not mine...mine is right here." Since the guard figures he's mistaken, he puts the phone back in the holding box...just like Fox planned.