Deliberate mistake: After they have the towels on the girls, find the "I Love NY" shirts. They're wearing white bras when they shouldn't have anything on, considering they just took a shower.
Deliberate mistake: When the two girls have get into the limo for the first time with the fake Chinese guy and they realized that they are now trapped and being taken away, there is a shot of one of the girls through the limo's window, limo windows aren't clear they are tinted so we shouldn't have been able to see her face.
Chosen answer: Before the girls go to the stall where the "I heart New York" shirts are, they broke into an apartment and Jane could have left her clothes in the bathroom when she was taking her shower, and Roxy could have left her clothes somewhere else around the hotel room. As for their towels and robe, they could have disposed of them in a bin or left them in the cubicles etc...
curiouskid