A friend of mine who is a teacher in California did not join the union, however she still must pay the same amount to a charity of her choice as long as the charity is from a union approved list. (Yes, they are all leftist charities.)
I loath unions.
The union here has two levels:
1) Everyone pays to work but you are not a "voting member"
2) Pay even more money, fill out a form that signs you up a a member, and you can vote.
I have never signed up. I have never joined. I always throw away any propaganda they send me. Yet, they still deduct money from my paycheck under the first reason.