Since the GBA didn't have a touch screen, I doubt the same warning was in its manual.
Hrm. Vernacular communication often works out quite logically. You just have to take the time and work through the kinks (or simply not be a sore thumb).
So, we have "warning". What is "warning"? The entirety of the quoted sentence might be the warning under question:
Prolonged exposure to the Nintendo DS touch screen may result in a higher risk of getting cancer.
However, there could also be parts within the quote that fulfill the concept of warning on their own. Apply one of these to the idea expressed in my previous post, and there is no fallacy:
Prolonged exposure may result in a higher risk of getting cancer.
The "touch screen" component in the original quote is secondary. You can take it out, and--logically--the quote fulfills all the requirements of a warning. This was the concept referred to in my post. Vernacular communication gives the benefit of the doubt in situations like these: We are not robots, and it is given that the active quality of conversation leads to learning for both parties. The start and the end are given. They're not even far apart. All you have to do is learn your way between them. Understanding people do it automatically without objecting to the pea-sized quantity of work.
I was tempted to go with, "You know what I mean."