You may be asked by your lender to state the purpose for your cash out refinance and, if they approve your loan, they may ask for proof that you have used the cash out money for your stated purpose.  The reason you request cash out may influence if your loan application is approved, but it’s unlikely to prove the difference.  It goes without saying that you won’t be approved for a cash out refinance if you state you’re going to use the additional funds for gambling.