"You fear them, but you do not fear them enough, yet."
After Frodo's disappearing act, the hobbits and Strider conference, with Strider offering information for a price, and generally playing up the mystery man role. Some of this is for Strider's own benefit as well as the hobbits', as it serves to test their wits and caution. I feel like Frodo's reluctance to agree to Strider's price (accompanying them on their journey) is exactly what Strider wanted.
I like Strider's self-awareness and deprecation. We don't yet learn the nature of his heritage, but Strider does know both his lineage and that of the sword he carries, neither of which necessarily induce humility in the bearer. However, I'm inclined to think that any arrogance on his part comes from expertise and long association with elves, rather than pride in his family and destiny. Elves do seem to have two modes: deceptively silly or stiffly aloof...
Pippin comes out the most diplomatic of the hobbits, with his "I daresay we shall all look much the same after lying for days in hedges and ditches." While even Strider admits he appears a bit "roguish," Frodo's comment about thinking the enemy will "seem fairer and feel fouler" is a bit... disparaging. It brings to mind the use of toxins as cosmetics, and though we'll see very few examples of "fair" seeming agents of Sauron, I can't help but feel that it's a good reflection on appearance vs. nature.
This chapter gives us quite a bit in the manner of reflection on the nature of people, in particular the darker natures of some. Unscrupulous Bill Ferny is not the first of his ilk they'll encounter on their journey.
Speaking on the nature of people, Butterbur comes in well meaning but misguided and with a letter that was meant to be delivered some time ago. Fortunately for all, Gandalf makes mention of Strider... and how to verify the correct one. Butterbur isn't quite on top of who's on the level and who isn't, painting Strider with the same brush as the black riders, but he does mean well. He is not a man for intrigue, and in matters of the ring, caution is worthwhile. He's rather hobbitish, round, protective, and fond of his home, but unlike hobbits he recognizes the name of Mordor.
Honestly, everyone seems more on top of the situation than Frodo, who determinedly plays dumb to Strider's warnings and hints. I have a feeling this observation is quickly approaching mantra status.
I find it amusing that in the book it's explicitly stated that Strider doesn't mention his association with Gandalf until it comes out in the letter, while in the film he name drops the wizard very early on. In both cases Frodo's reactions are believable, be it the wariness of a stranger who seems to know too much or the excitement of someone mentioning the sought-after Gandalf. I fully believe that Frodo would have willingly trusted the first semi-knowledgeable person who knew of Gandalf and who wasn't dastardly twirling their mustache.
Now, clearly the letter in Butterbur's keeping would have served us all well has it been delivered in a timely fashion. Gandalf's urgent leave by date is long past, and that whole "do not travel at night" warning might have cut out a few close calls.
The letter also gives us words that are incorporated in perhaps one of the most iconic rock songs I know of, Stairway to Heaven (for those interested in reading more on Tolkien's influence on rock and roll, check out this article by Rolling Stone and this Wikipedia article). Note, I do realize that Stairway's connection to Tolkien is considered more tenuous than the songs that explicitly reference Middle Earth (such as Ramble On), I have this mental bridge to "not all that glitters is gold." Regardless of my potentially biased connections, Middle Earth comes up again and again in rock and roll.
The lyrics are very relevant to the story itself, as Aragorn's journey is as strong of an arc as Frodo's journey. The mission to destroy the ring, the looming war, and the vanishing elves are all pieces of the end of one age and the start of a new one.
Merry's absence is noticed almost as an afterthought. As a reader I wasn't even tracking it until the Pippin mentions it offhand! But Merry is soon after brought in by Nob, takes it on to make up their beds as if they were asleep within when he goes to fetch their luggage. Aragorn is amazed at the risk Merry took, but clearly he's not familiar with the inquisitive nature of hobbits, nor of their unexpected bravery. Of course, if my memory serves me right, this is far from the last time Merry will take outstanding risks as part of his curiosity.
Aragorn is our first really connection with the greater world completely outside the Shire. Both Gandalf and the Black Riders come from outside of the Shire, but they were introduced to us within those bounds. Perhaps it's his role as a true outsider that allows him to best serve as a guide to our hobbits, both in terms of the road ahead and in enlightening them to information. Among other things, he drops this gem: "Gandalf is greater than you Shire-folk know - as a rule you can only see his jokes and toys," which also fits into what I've talked about in The Hobbit about Gandalf as a trickster.
Going on to the film, Jackson does a fantastic job of showing rather than telling. Much of the dialog and even additional participation is cleanly cut out. We never meet Nob, Butterbur fails to show up with the letter, and Merry never goes sneaking after the Black Riders (who never meet with Bill Ferney... these Black Riders are not the type to consort with your normal mortals beyond intimidating information out of them).
The scene neatly transitions from Frodo's donning of the Ring to Strider dragging our clumsy hobbit to a private room to chide him for his foolishness, lack of fear, and lack of respect for what he carries. As I mentioned earlier, Jackson not only cuts out the letter, but has Strider nearly start with name dropping Gandalf. Merry, Pippin, and Sam get to showcase their protective nature by storming the room to rescue their friend, who at this point has already been largely convinced of Strider's benevolent nature.
Bill Ferny becomes a victim of the Black Riders rather than a conspirator, in a moment of slapstick body humor as the Riders knock down the gate and ride into town. I think it more likely that our hobbits or Aragorn made up the beds instead of the invisible Nob, to better keep knowledge contained. All we see are shots of sleeping hobbits interspersed with shots of Riders stalking up to the beds and raising their swords to strike. It's not until after they strike that the duplicity is revealed to all, and their cries of rage wake the hobbits, leading to storytime with Aragorn.