the dominant mode of appeal would be pathos. the gun being wrapped in caution tape plays with the imagination. the imagery alludes to, and makes your mind picture, crimes scenes and other dangerous situations. the poster uses the rhetorical trope of synecdoche. the viewer is given a piece of information with the gun and caution tape, for which they are left to use their knowledge to make connections to the more complex scenarios that demonstrate the consequences of guns. there is also a bit of a pun with the wording, another word for caution can be beware. and in this case for gun control we also need to “be aware” of the dangers surrounding gun usage. maybe that’s stretching it. i believe the design’s simplicity is bold and gives off a clear, straight forward message.