Because these tenants have no money. If they did, they'd likely be buying properties and listing them instead of doing these illegal sublets. The landlords in t

Because these tenants have no money. If they did, they'd likely be buying properties and listing them instead of doing these illegal sublets. The landlords in the area will likely drastically increase the rental deposit (unless it's limited by state or local law to some multiple of the monthly rent). That's the only real security against a tenant.