LARPing is roleplaying because you are, wait for it... playing a role! Mechanics like dicerolling have nothing to do with it. They are just a medium to simulate the results of choices. Is Fallout 4 technically an RPG? Yes, in the same sense that Minecraft is a first person shooter. The elements exist, but only in the most basic of basic formats, and we're talking REALLY bare-bones here. It isn't what most people think of when they say a game is an RPG. Scrolling through dialogue and making meaningful dialogue choices is one of the most important facets of an RPG. It informs the choices you think that character would make in that situation. Making choices based on you character's um... character... is the line in the sand that divides an RPG from a non-RPG. It is the only factor. Does Fallout 4 do this? Sort of... a little... not to a satisfactory degree. I would never promote it on the basis that it's an RPG.