The main concern for parks not allowing secured cameras boils down to safety and liability of the park. No one wants an accident to happen and for smaller parks this could be devastating to their business. Universal Studios and Islands of Adventure have gone to the extreme of reducing their lability by installing high level of security of both metal detectors and security wands at the entrance to major rides. They have also installed lockers for guests to place ALL their loose items so that there is minimal accidents from loose objects. One of Islands of Adventure's rides "The Incredible Hulk Coaster," actually passes over guest pathways, which could seriously cause an injury if an object were to come loose. Many parks have installed netting underneath the track at these locations to help prevent foreign objects from causing injury.
When parks do film their on ride footage for promotional use, some close the ride to guests and clear the area so that the risk of injury is minimal as the case of Fun-Spot America in Orlando, FL. This way the park is totally responsible for any liability for their employees and not their guests while filming. However, another small park Knobel's Resort in PA, has a hands free camera policy built in place that allows their guests to film. So why do some parks allow hands free cameras and others don't? The bottom line is risk tolerance and liability. If there is a slight chance of any item, even a properly secured action camera, to come loose and cause injury, then those parks will not allow action cameras period. Parks that do not have a hands free camera policy in place or allow their guests to film safely have a low risk tolerance and are less liable. So how can parks like Busch Gardens, SeaWorld, and Knobel's Resort allow hands free cameras? They apparently have taken the time to test various mounts, cameras, etc. to come up with a policy that works best for them and therefore they have a higher risk tolerance than those parks that don't. Perhaps there are different levels of liability insurance that may have a high coverage that allows parks to have a hands free camera policy.
How can lower risk tolerance parks like Six Flags, Cedar Fair, Silver Dollar City, Holliday World, etc. allow their guests to film safely, but have minimal liability to the park? One simple way would be to have a "ride at your own risk" policy in place where guests would sign a waiver as part of their ticket entrance to the park. Paintball fields, ziplines, and other types of extreme sport attractions require their guests to sign a waiver. This is one way major amusement parks could allow their guests to film safely and still keep their liability cost to a minimal.
Amusement parks can try to prevent injuries by having strict park policies in place when it comes to their attractions and training of staff. A few ideas might be to help increase rider safety would only allow a minimum age of 21 to operate amusement rides. Even still, accidents will happen and not all guests will be responsible and follow the rules. Guests may put away their cellphone in their pocket, but because of the nature of the ride, something will fly out eventually. However, a properly secured action camera that is secured via a chest harness, or hand mount is NOT going to fly off and cause injury. unless the guest themselves tampers with the locking device while they are on the ride. If you are worried about liability then don't go to the amusement park or be in the amusement ride business. Accidents are going to happen whether it is the fault of the guest or park. Guests need to understand that when they get on a ride there is always a risk of injury or death just like getting in your car. Parks will do their best to provide the necessary safety precautions through daily inspections, employee training, continuing education, etc. A signed waiver "ride at your own risk" would greatly free up the liability cost of the parks.
Having a ride operator training video about action camera safety and educating about proper procedures, devices, etc. would greatly help eliminate the use of unsecured devices such as cellphones and loose cameras. There are ways to not slow down the flow of the ride by inspecting secured cameras and wouldn't be that hard to implement. Guests wanting to use a secured camera would go to guest relations where a manager would inspect their equipment and sign off by giving them a pass. This pass would then be shown to the ride operators at the entrance of the ride. Busch Gardens Williamsburg and Tampa already have this in place.
