I'm thinking that he picked up the jacket from CA to take to KC and she put the bracelet in the pocket without telling Baez. It just sounds so CA.
ETA: If it was in the socks I definitely think CA. JB would know that those socks would get turned inside out before giving them to KC.
ITA - we don't know that JB is the one who tried to sneak anything - I think he has much bigger things to worry about - this sounds so like CA it isn't funny - a little "I'm still here" token...no way JB or his team did this IMO...I also don't think they felt that they needed to search the whole outfit - it never occurred to them anyone would try this stupid trick.