Nothing contained in this chapter applies to educational services performed by an institution, school, or nursery school if the care and maintenance of children is only incidental to the operation of the school, to services performed by summer or recreational camps designed primarily for character building or recreation, to the care of children by a relative, to the casual care of children by a baby sitter, or to the exchange of care of children by parents under informal mutual arrangements, to care furnished by a guardian or by institutions operated by other departments of state government.
For the purposes of this chapter, "casual care of children" is employment which is irregular or intermittent and which is not performed by an individual whose vocation is babysitting and which does not exceed twenty sitter hours rendered to not more than six children per week.