Impaction risk varies from species to species, and even individual to individual within a species. There are so many factors that contribute to whether or not an animal will become impacted that there is no simple 'one and done' solution to the problem. Stress and overall husbandry plays a huge factor in processing food, along with the size of the prey item and quanitity being fed, and the size and anatomy of the herp. Some herps simply don't have a digestion system built to process these food items...Bearded dragons for example have a very poor digestive anatomy and often suffer impactions far easier than other herps due to the way the pyloric sphincter is set up. You'll find that impaction risks almost seem non-existent in some species but happen routinely in others.

Chitin is the culprit of impactions, but what a lot of people fail to realize is the exoskeleton of all common feeders is comprised of chitin... it is a complex, structural carbohydrate much like cellulose in plants that is incredibly difficult to digest. Some feeders have more chitin than others and some feeders have overall better meat:shell ratios. Superworms and mealworms are example of species that have very high chitin content in their exoskeleton.

Simply punching holes into an insect won't prevent impaction... and the scientific method to come to this conclusion was clearly not outlined ; ) No offense, but just because you tried something and impaction didn't result, doesn't mean that it will be a universal truth. There are plenty of keepers who feed mealworms and superworms exclusively and plenty of keepers who keep reptiles on sand and other particulate substrate that is responsible for impactions and never have issues...then there are the many who do have problems and the result is often detrimental for the herp. Chitin is not a readily digestable polymer and reptiles simply lack the enzymatic activity to properly metabolize it. If the exoskeleton is being consumed, it can cause blockage plain and simple.

The only way to stop an impaction is to prevent it in the first place. Feed appropriate food items for the herp you own in the proper quantities and provide proper husbandry.