You can, but that means you are giving them charging and you have to sign that you'll cover any overage.
There is NOTHING done as part of the programming in any age group that has any fee with the exception of the Wild Side excursion on
Castaway Cay (and you sign up for this thru port adventures). There is a "bar" in the teen area where they can purchase smoothies or sodas when they are not part of the programming. By that I mean that if it is free time in the Vibe and your kid wants a smoothie, she pays. If it is Smoothie Party, each kid in attendance gets a free smoothie. If it is "make a t-shirt," each kid participating gets a free t-shirt to decorate. If it is "Invade the Arcade," all the games are set to free play for that hour.
I told my kid that if I EVER saw a charge for a soda because she was too lazy to go to the beverage station, it would be the last money she'd see from me. Sorry; no excuse for plain laziness in my mind. I worked hard for that money. I would give her an amount (usually $50) and explain that it was enough to buy a smoothie each day and something small in the gift shop...and that if she chose to not spend it on vacation, any left overs would be given to her in cash after the cruise (it eliminated the purchase she didn't really want just because she had money!). Worked for us......
So no, if you don't want your teen/tween to have charging, it will not affect how they can participate in the Vibe or Edge at all.