It's also heavily implied in this episode that anybody found without means to provide for themselves is immediately shipped into the districts without recourse or path to release.
Sisko and Bashir were taken to one of the Sanctuary Districts because they lacked ID's, indicating (apparently) that they were homeless.
Once in the district Sisko and Bashir are assumed to be "gimmes." people in need of employment and a place to stay. The district does
provide a job placement service (which is hampered by a bad economy).
Prior to about forty years ago, homeless with mental impairment could be remove from the streets to a treatment environment and held there, where some improved and some did not. In the early 1970's (in America) mental patents gain the legal ability to leave anytime they wished to. The court system considered this to be a right, For many this meant living on the streets, isolated from treatment.
Bashir notes that some of the people in the district are mentally challenged. These are the people referred to as the "dims." The police initially think Sisko and Bashir are dims, owing to their confusing statements.
While people with criminal records are supposed to be excluded from the districts, there is gang activity, these are the "ghosts."
It's implied that if Sisko and Bashir possessed identification, regardless that they had no money or jobs, that they would never have been escorted to the district.