It&#x27;s a special case of the more general case of taxation of non-market services.<p>Say A is a stay at home dad, B is his spouse, and C works at an office. B and C both make $10 per month and there is a 20% flat tax. So total tax revenue is $4. Now, say that A wants to live a life of leisure. So he hires C to do nannying on the side, and they pay her $3 per month. Now, total income is $23, and total tax revenue is $4.6. But the same amount of work is being done as before! All that&#x27;s happened is an activity moved from the non-taxed domestic realm to a taxed market one.