The obligation is there for the reason why it's imprinted on the package... It contains small parts which can be swallowed and then the warning must be on it, whether it be a toy or an everyday object or even when a sex toy. If you have a pair of these in your house and you forget about them and your 2 years old kid kinds them and swallows the small parts in the process with all the medical issues that gives you'll realize that warning is on the package for a reason.
As a rule anything is a mortal killer when it the hands of a kid younger than 3. Since we adult people do not always realize this, such warnings always come. Now on a sex toy the way the warning is formulated may seem a little awkward, as perhaps "keep out of reach of children below 3 years" could have seem a bit less awkward. Still the warning must be on the package, and for good reasons also.
