Help defund the unions by forbidding the use of state funds to collect union dues

Today I had an absolutely BRILLIANT thought (if I must say so myself). Why not make it illegal to use state funds, computers, and personnel to collect union dues? I mean, why should the state have to spend taxpayer money to collect the union dues and distribute them to the unions? Make the individuals contribute the money themselves through an automatic band draft or write a check. The unions will have HELL trying to collect their dues!