I emailed Universal asking about fanny packs and this is the response I got.
"Dear Ms. Stauffer,
Thank you for contacting Universal Orlando® Guest Services.
For the safety and security of our Guests and their belongings, loose articles, such as a fanny pack, are not permitted on many of our attractions. Given the safety features, dramatic movement, and dynamic nature of many of our rides, an exception cannot be made no matter how securely the fanny pack is attached. I apologize for any disappointment this may cause.
Universal Orlando® strives to offer each Guest the best theme park experience possible. As a part of this experience, we provide lockers in which our Guests can store their personal items while they enjoy our attractions. Please be advised that Universal Orlando® is not responsible for any items that are lost or damaged in our resort. We recommend that you bring only basic essentials to the parks and leave valuable items at home or in your hotel safe.
If you have any other questions or concerns, please feel free to call us at (407) 224-4233, option three (3).
Again, thank you for contacting us."