If their visa is B2 visa, they will usually get 6 months on their I-94. So, if they get I-94 for such long or anything more than 10 days, they are free to stay and move around. From visa standpoint, that’s the process…check with Thomascook on the logistics and if they are applying for B2 visa and then plan it accordingly…Everything is tied to the I-94 date, so plan accordingly.