Many years ago there was this such deduction. It had to be during 1984-1986, since it happened at one of my past jobs.
A new partner merged into the firm, and I became his sort-of fair-haired tax guy(when I had hair). He told me that all of his clients, INCLUDING THE CHILDREN, were to get the $300 above-the-line deduction.
I refused unless they had proof. Then when HE WAS FIRED, he asked me to come along and be his tax partner.
I refused again.