I have been fortunate enough not to have to deal with mites. However, I do keep some PAM on hand just in case of my new babies comes home with them.
To the OP, buying some PAM (Prevent-A-Mite) is not a bad idea to order and have laying around. Then if you do get a snake with mites, you can treat it pretty quickly and not have to wait around for it to be shipped to your door.