My cousin is taking her 17 yr old twins to Universal for a week in July. The girls will turn 18 on the 3rd day of the visit. Are the child room keys different than the adults? Someone at work told her that they will charge her an extra $25 per person per night for more than 2 adults in the room (which is what they will be considered when they turn 18). I told her I didn't think it was necessary to tell them of the age change mid trip. Any thoughts??