Instead the two girls could hold two dummy (fake, empty) laptops/netbooks/tablets in their left hand (or they could even attach the dummy laptops/tablets to their hands/arms, to make it easier for them). This is much more consistent with the song and also because both the two girls have the dummy laptop/tablet, it creates symmetry on the stage.
You didn't notice that one of the girls was holding what appeared to be a camera then?