How Lenders Verify Owner Occupancy

[Kwaku Farkye]

I recently went to Wells Fargo and they're offering me 5% down on an owner-occupied duplex (I think it's a program they have for first time homebuyers). I'm all for playing by the rules, but how does a lender even verify that a home is owner-occupied after they provide the loan?

It'd be nice to start renting out the owner-occupied unit and receive income from both units. What's to stop me from renting out the owner-occupied unit? Is there a penalty of some sort if caught?

The only thing I can think of is taxes, where I'd miss out on some incentives because the home is a primary residence and not an investment. Any help understanding this is much appreciated.