Disney has three rules concerning coolers in the parks.
1. The four major parks allow "small, soft-sided, coolers".
2. The water parks rule is if you can carry, drag or wheel it you may bring it in.
3. However, nothing in glass containers and no alcoholic beverages are permitted.
In recent weeks I have seen: Starbucks cold coffees, Snapple, IBC root beer, pickles, salsa, Mayonaisse, hot sauce. All of these are in glass. We give people four options: (1) return item to car, (2) put item in trash, (3) we will provide large paper cups to transfer and then throw away container, or (4) consume the item on the spot and throw away the container.
I did allow one exception, when I saw someone bringing in two 10ml bottles of insulin since I know they will not break if dropped.