During tonight's ep, when Nick and Starr arrived at the bakery, the taxi driver tried to hand them something that looked like papers to me. Nick and Starr didn't notice and walked away, and the rattlesnake sound effect of screw ups was heard. The fact that this didn't come up at all during the rest of the episode, but that it was noted with the sound effect, makes me think that it's going to be important next episode. In other words, I think Nick and Starr left their passports behind at that moment.