This is one of those cases where localisation seems to have taken into account culture rather than just translation. In Spanish and Italian, you're told it's dangerous to hang [from the arm]; in French, you're not told it's dangerous, you're just told not to hang; in Chinese, you're told it's forbidden. In German, however, you 're merely requested not to hang off the arm.
In English, there's nothing about hanging off it at all, you're just ordered flat out not to grab it. I guess that's because we English are such brutes that we don't need to dangle from an arm to break it, just taking hold of it is enough.
As for the picture of the stick man, it looks as if he's about to club something to death.