Our experience 2 weeks ago.....
We are a party of 4 (myself, DH who is type 1 diabetic, DS15, DS8). We always take into any park a backpack cooler with bottled water, a gatorade for low sugars (which happen often in the stressful heat and humidity of a themepark), and a few granola bars or packs of cookies in case someone gets peckish between meals. My DS8 can get very challenging if he is hangry, but sometimes situations arise where we can't get him a meal right when needed so this gets us over the hump. We knew the policies at SeaWorld and Aquatica, so were prepared to go to Guest Services if an issue arose. At SeaWorld, our bags were never checked. My husband was wanded at the metal detector because he set it off with his medical devices but otherwise never checked. At Aquatica, our bags were checked, and no one said a word or asked him about his Diabetes/medical devices. Again, we weren't taking in a full meal or substantial food, so that may have been the key, but we didn't have any issues with the gatorade and a few granola bars.