Greg:
Yes, there are differences between Fla. & NJ
How do we (Code Enforcement) aka Bldg Dept. find the 'issues'??
During re-sale CCO inspections.
Neighbors dropping a dime.
Contractor disputes. (Yes, some get themselves in deep)
Drive-bys. "Gee, what is that 100' crane doing??"
"Where did that pylon sign come from"
"That gas station was not like that last Friday"
"New neon is a retail that had a final last Friday"
"Brown paper covering windows"
Three doorbells & mailboxes in a single/two family neighborhood!
Believe me, it's not Sherlock Holmes work!!
BTW, 'destructive inspections' are a rarity. The illegal apartments being an exception. They get violations/fines, require permits for whatever demo.