"if caught" : how would that happen? You go to sell the house and the buyer demands to see all your permits? The city inspector barges into your house uninvite

"if caught" : how would that happen? You go to sell the house and the buyer demands to see all your permits? The city inspector barges into your house uninvited? Unless you're in a total buyer's market, you just sell to someone who isn't so nitpicky. Or you get a pro to inspect your work and attest that it's up to code (it would be, wouldn't it?)