I thought the tags would give it away, but I've added a note to the bottom of the G&S as requested - and referenced the drop bear.

Given the nature of this site, if this critter doesn't exist and is merely a hoax, we should really be more overt about that fact. As written, this is pretty dryly subtle. Last thing you want as a GM is to be narrating a bit of color about a location the PCs are visiting that you've never been to, only to have a player call you on your factual inaccuracy. It'd be pretty easy to overlook said tags.

In general, arcanawiki pages can be trusted to be honest about whether or not the topic is factual… we don't usually lay boobytraps for our fellow gamers. We have plenty of pages here on fictional / mythological / folkloric, critters and characters, not to mention actual hoaxes, alternative science, and conspiracy theory. If it's some sort of local joke for picking on foreign tourists like the "drop bear" that actually makes it somewhat more flexible in a game, and would be worthy of mentioning in the "game and story use" section.