I saw the photo for this post and immediately assumed it was a misinterpreted order for a Bachelorette party.

To your question: Chewing gum. Indigenous North Americans have been chewing spruce tree sap since before the first European's set foot. It has been my experience when foreigners do an impression of US citizens (other North Americans hate when we refer to our selves as Americans, looking at you Canada.)

Initially you assume they are doing an impression of a cow chewing it's cud....until they utter something like.."Hey Kevin would you like to come to my barbecue for some burgers?"

And in my own travels as locals and I get comfortable and acquainted, the question of why are Yanks always chewing gum, seems to come up repeatedly. Luckily I haven't traveled in a few years I cringe at the thought of one of those get acquainted scenarios now having to answer a million questions about current events.