If you want your bridal party to have professionally styled hair and make-up, are you supposed to pay for their appointments?
If you are going to require your bridal party to get their hair and makeup done for the wedding day then I think you should offer to pay for the expense. Some of my clients allow their wedding party to decide for themselves whether or not they want to get their hair and makeup done. If it is an option for the girls, then you can say something along the lines of "I have a stylist coming if you would like to use her. She charges x for hair and x for makeup. If you would prefer to do your own, that's great too!" This gives the ladies the option without insinuating that you are covering the expense. However, again, if you are demanding they get their hair and makeup done, budget some extra dollars for this expense.