Many families skip household employment taxes, more so in the past that in recent times. The IRS is most serious about “under the table” or cash arrangements, however, treating them simply as tax evasion, which is a felony.
Household employment taxes are part of your personal Federal Income Tax return, which you sign under penalties of perjury. Besides, you’d be easily caught when one of the employees you did not register makes a claim for “Unemployment Benefits”.
Finally, even if you were routinely audited by the IRS years later and this came up, you’d be facing difficulties, for there is no statute of limitations on the failure to report and pay federal payroll taxes.