You can bring so much into the parks, but there are some restrictions for the safety of cast members, guests and to keep the parks as clean as possible.
Weapons: While I'm sure this item is something everyone would know out of common sense, you would be surprised at how many people still attempt to carry them in the parks. It's not just about people carrying just because this is what they do at home. Disney has been one step ahead of some bad people out there with bad intentions, too. This is one of the reasons why the parks have metal detectors. Disney has some of the best security in the world including behind the scenes. It's not just about people checking your bags, strollers and wheelchairs. There are security people you don't even see who are actively working to prevent a tragedy from occurring. There are cameras everywhere for your safety. So, just remember that when prices go up. Your safety is their top priority.
Folding Chairs: Mobility Aides are allowed, but chairs are not. This is a hazard for the thousands of guests walking around and for the person sitting.
Drones: No drones, toys or any other remote-controlled flying apparatuses.
Most items on wheels: Strollers are required to be no larger than 31" (79cm) and 52" (132cm) long. Wagons (push and pull effective May 1, 2019), bikes, suitcases, roller skates, roller blades and all other items on wheels are forbidden. (Wheelchairs and mobility aides are allowed.) These updates are designed to help guest flow and ease congestion, making the parks more enjoyable for everyone.
Pogo Sticks: I don't see how using something like this would ever be possible, but, apparently, people have tried. Bouncing around like an uncontrolled Tigger is not allowed.
Wrapped Presents: Because Disney does not have x-ray machines and rely heavily on their security to check the bags, no wrapped presents are allowed at any time. Security must be able to see every single item you carry in the park.
Selfie Sticks: Say it isn't so! It would be great to use a selfie stick at Disney, but, alas, they can cause injuries to other guests, problems on attractions, etc. Leave it at home. No exceptions. Even if you try, it will be confiscated at security to a secure location for you to pick up when you are leaving the park. Either use your arms or ask a guest to take a picture for you if there's no Disney photographer around.
Ashes: We all love Disney and we have some family who would love to have a piece of them left at their favorite place on earth once they've passed, but this is forbidden. Remember the cameras I talked about above? The cameras have caught people trying to release ashes they managed to sneak into the park. The attraction is abruptly stopped, the guests are escorted off property and the attraction is shut down to be properly cleaned. I don't know about you, but I wouldn't want to be escorted off Disney property and possibly be banned for life because of dropping some ashes.
Ice: Loose or dry ice are not permitted in the theme parks, but you can bring re-useable ice packs.
Smoking: Smoking areas will no longer be present inside Walt Disney World or Disneyland theme parks, water parks, ESPN Wide World of Sports Complex or Downtown Disney in California. Designated smoking areas will be available outside the entrances of the areas listed above and at Disney Springs in Florida. For guests who have room or dining reservations, smoking areas are also available at Disney Resort hotels. (Effective May 1, 2019)