Usually when going to a Disney park we bring a bottle of water and crystal light to flavor the water and that we can refill without going broke. In addition, both of my children 8 and 6 carry fanny packs with a couple of snacks in them. Can we do this at Universal? How stict are they? We plan on buying our meals there, but I have a hard time spending an additional $20 plus on drinks and snacks. TIA