LotR -- Book 1 - Chapter 05 - A Conspiracy Unmasked

[Firefoot]

the hobbits are being very hobbitty, but unlike the Party with which the book began, it all seems so much more fragile here.

Exactly! It is something of a pretense over the darker dangers and undercurrents which they know are there but do not quite want to acknowledge yet. It brings to mind Merry's words in the Houses of Healing (not to stray too much from the chapter...): "But it is the way of my people to use light words at such times and say less than they mean. We fear to say too much. It robs us of the right words when a jest is out of place." It is the way of hobbits to talk lightly of such things. Even though they fully (or not so fully) understand the dangers they face, they do not speak of them in deep dark ways.