Common Sense isn't So Common
One of the difficulties in these kinds of scenarios is that the writer tends to think that these sorts of meta-goals are common sense, but that sort of thinking is lazy writing. What one person thinks is common sense is not the same to others.
So what do you do to make up for this kind of lazy writing?
Show, don't tell
As a game master, it is not only the rules of the game that you are adjudicating, but the whole mood. And your best tool in doing so isn't the rules, but your example.
In general, this makes for a more engrossing and immersive game; when the players can see things and make the threads come together in character and respond to your lead.
To give an example, when the players first come into town, do you merely start into the encounter? Or do you give flavor that may or may not be in the module as written? That flavor is important, and if framed right can help give hints into the systems that lie behind it.
As the sun begins to set over your shoulder, it illuminates the town in front of you in fading shades of red and orange. The people move along their daily routine, finishing their orderly days by taking in stock from the tables that line the street in front of their stores. It appears as if by night, the town will be completely asleep- other than the building at the end of the street, to which people seem to be flocking. An older child, helping finish the task for the day looks up shading his eyes at your entrance into town, and gives you a furtive wave. Seeing your weapons, and gear, an older man pulls him aside and speaks in low tones. The boy looks at your party with widening eyes before the man cuffs him on the head and points to work left undone.
As he prepares to get to his unfinished work, he looks across the street, and his eyes open wide again. He leaves the pile where it lies, running inside. Looking to what caught his attention, you see a group men step out of the shadows of the alley into the street. You wonder what they might be thinking- you're obviously better equipped, trained, and able than this riff-raff.
"New to town strangers?" the lead one says, stopping only when he's in front of your group in the street. The others keep moving, intending to cut off your progress.
You hear the sound of running from behind you, and see the young man beating a hasty path down the street, the older man watching his progress from the door of the store.
Show them what kind of town it is. Show them in the eyes of the inhabitants, and their actions and words. Allow them to get information, using the skills that they have... and don't make them roll if it's not necessary. If someone asks a question about the feel of the town as the escalation seems imminent, tell them- don't make them roll for it.
Conclusion
In the end, other than outright telling the group, there's no way that they're going to know everything. But you can do your part to drop the clues necessary, and then not let the system stand in the way of giving them the information they need if they ask for it. And then, if they don't ask, if they don't get the hints... well, that happens sometimes. And they can see the results, and those results can inform future decisions, as sometimes you have to fail before you can succeed.