Hospitality

Roads and streets are rarely ever completely safe. Bandits, thieves, and monsters of all sorts can be found virtually anywhere. Over millennia this fundamental truth has shaped a strong sense of hospitality across all nations. Travelers who wander to a lone cottage and knock on the door can expect to be given food and rest with little worry of denial. The majority of people, if approached by a stranger needing help on a normal day, will be compelled by the notion of hypothetical reciprocity. "If I were in their shoes, I'd want to be supported." This mindset of potential need means that there are relatively few instances of hosts being taken advantage of or downright deceived by guests. If a thief or bandit comes to strike a household, they will very rarely knock on the door asking for hospitality. Those who do are considered shameful and despised by any who know of this behavior.
This is not to say that people don't get turned away. Extenuating circumstances may cause a normally-hospitable person to turn a traveler back to the road. Others may have the reputation of a constantly closed door. But there are major social implications for this. A repeatedly inhospitable person our household can expect to be shunned by the nearby community even in very dire circumstances.
These expectations are even more likely to upheld during winter. The sheer danger of winter conditions compel people to show empathy to those in need.