When I first found out about the Warning Out of Jonas Joslin from a distant cousin, I had no idea what a “Warning Out” was. After having read various articles online and the introduction in “Vermont Warnings Out” by Alden M. Rollins (Picton Press, Camden, Maine, no date) I've decided that the basic premise seems to be that town selectmen were taking precautions so that they would not be held responsible for caring for new inhabitants coming into their town.
An article on Wikipedia states that warning out was a widespread method for established New England communities to pressure or coerce "outsiders" to settle elsewhere. It consisted of a notice ordered by the Board of Selectmen of a town, and served by the constable upon any newcomer who might become a town charge. When a person was warned out of a town, they were not necessarily forcibly removed.
The article on Wikipedia cites Warning out in New England by Josiah Henry Benton as a source. Published in 1911 and digitized in 2006, it is available on Google Books.
There was a distinction between a resident and an inhabitant of a town. Apparently, simply living in an area made you a resident, but to become an inhabitant required being a resident for a year. If, within that year, the person was not “warned out” they would then become an inhabitant and would thus be allowed to remain in the town. By warning out residents, the town would be spared any future liability for the resident in case of poverty.
According to Warning Out by Darrell A. Martin, A "warning out" was simply a legal formality. Regardless of whether the person or family departed, the warning served to absolve the town of any future responsibility, and so whether the person warned out actually left made no difference. Some warnings really were issued to transient indigents, and some went to folks who were just passing through on their way somewhere else. On many occasions, perhaps even in the majority of cases, the person warned out settled in town, bought property, and in all respects became a productive member of the community.
Also according to Mr. Martin, the warning “frequently included every member of the family, by name” but in the records I saw in the Charlotte Town Records, very few entries, if any, included names of other family members – they simply listed a single individual, presumed to be the head of household.
An interesting article by Brian Deming is Warning Out – Casting Out the Poor. Mr. Deming states:
In Colonial New England, each town was responsible for the care of its own widows, orphans, elderly, disabled, hungry, and sick. Every town seemed to make some effort to see to it that no one starved or froze to death. Some towns arranged to pay willing citizens to take in the destitute. To be eligible for charity, a person had to be a legal "inhabitant" of a town. An inhabitant was anyone born in the town. One could also become an inhabitant by acquiring land in the town, by completing service as an apprentice to a master in the town, or by marrying an inhabitant. Anyone not a legal inhabitant was not eligible for welfare and could be warned out.
A person could be warned out without being forced to leave a town. Many towns had a policy that, if you had not been warned out in more than a year, you were officially an inhabitant and therefore eligible for welfare. So some towns would routinely warn out “outsiders” that they thought might be likely to fall into poverty and even those doing well. Those individuals could remain in the town even after being warned out year after year. Some even established businesses. It was thus possible for a person to pay taxes in a town for years to help others in need, but then after bad luck be ineligible for welfare in that same town because they themselves had been warned out.