"Sometimes easier to open" may man one of these:
- there are some child-resistant packages that are easier to open by children
- there are some chilren that find opening child-resistant packages easier than adults
- there are some reports of children opening the child-resistant packages easier than adults
This division is important, because each of the three means something else:
- The first one focuses on the object. Being able to say that a package is easier to open by a child than by an adult person is something behind statistics and can be considered as a rule. Thus, while constructed with intention not to be easily opened by children, the construction of these packages is obviously a failure.
- The second one focuses on the child. It still allows to form a rule about a package being more easily opened by a child but only if this child has some over-average abilities (like strength, manipulating or intelectual skills), so this rule would apply only to a selected group of children.
- The third one is random. It says that there are situations like this, however no specific regularity can be assigned to them. I mean, it’s a lack of such regularity, not insufficient data collected, allowing to assign these situations to one of the former groups. In the same time, the scale cannot be too high, because having it at high level would automatically make it fall into the first group.
Now, it’s hard to analyze randomness, but it is possible to focus on the child and object. Let’s start from the child-point-of-view approach. First of all, child is a user; in fact, there are two types of users of a child-resistant package:
- adult (the intended user)
- child (the unintended user)
The tricky part is to make the package accessible for the intended user while keeping it totally inaccessible for the unintended user. It is a very difficult task because of these factors:
- within the population of adults, the skill set can vary (namely: it can be lower than average)
- within the population of children, the skill set can vary as well (namely: it can be higher than average)
These two factors make it necessary to increase accessibility of a child-resistant package (to make it possible to open for a "weak adult”) while decreasing its accessibility in the same time (to make it impossible to open for a „strong child”). These two are quite contradictory, however, it is still possible to find some ways of securing a package in such a way that would make it less possible for children to open it while keeping it still quite easy to open for an adult. This is actually the idea behind child-resistant packaging anyway. The skills that are mostly considered in this case are a combination of strenght, manipulation skills, knowledge and intelectual skills):
- strength and manipulating skills, as requirements to open the package, are necessary to push the nut and unscrew it while pushed
- knowledge and intelectual skills are in the same time necessary to be aware of the way of opening the package. It is very important that usually a child simply cannot gain this knowledge by trial and error - it will fail on the strength and manipulating skills requirement, so no success for a series of such trials is possible (again: usually). However, this knowledge can be gained from observing an adult or a child might develop this idea itself. (And sometimes no experience at all is the biggest advantage of the ideating process!)
If any of these requirements is fulflled, completing the other ones becomes simple. If a child has great strength - it will easily open the package after some trial and error game. If it has knowledge - sooner or later he or she will find maybe enough strength, or use a tool, to open it. A bare idea has some question mark somewhere, but it leads to the same result in the end. As in fact it ie easy to guess or gain a knowledge about opening a child-resistant package, the real limitation should be put in strength requirement.
One more very important thing is that children are a very broad category of users, no matter if these are intended or unintended user. This means only that within the group the skill set is very different, based on factors such as age, environment, innate skills, development etc. In the same time, the intended users of a vial of medicine can be - in many cases - persons with limited strangth, older people with limited intelectual skills („I don’t know how to open it, sweetie.” „I will help you, grandma.”). So we are back to skill set overlapping. In big population, there is no way to avoid it to overlap, and thus there is no way to avoid situations in which children are able to open such packagings.
However, it is not opening child-resistant packages that is a source of the problem (or rather: a threat) of children overdosing a medicine. Not always this skill leads to such consequences. With age, children usually gain more strength, knowledge and they develop their manipulating and intelectual skills. In the same time, they develop also a sense of responsibility and consequence. Both of these developments are though paralell, and it is very probable, that a child will have enough sense of consequence when it develops skills for opening such a package.
This topic could be easily extended to more areas (such as electric socket blockers, door and drawer locks etc.) but I think that it all falls into the same scheme at this level of generalizing.