Transit and dresscode are 2 completely different effects. To answer your question, no I don't think this is dresscode. Calen wasn't the first to come up with a method for a shirt change like that. If you noticed, Cyriland Calens presentation are different. Calen presents the effect like he is wearing only one shirt (underneath) then it changes to another, Cyril took a shirt off the rack and presented it like he was putting it on without having to take off his over shirt. Cyril actually has a few videos online showing this same trick.