@Robocop2020
In one scenario you are giving the fair rental value of property you own to your son free of charge; that would be a gift of the fair rental value of the property.
In the other scenario, the income has already accrued to your benefit and, as such, has to be reported as your income. You cannot disclaim income after the income has inured to your benefit; you can only report it and then gift the income subsequently.
Note that it does not matter whether you actually receive the income as long as the funds are available to you in one form or another. Further, income-shifting is looked upon with extreme disfavor by the IRS so use extreme caution.
