If they don't want to join the union, there should be two pay scales:  The one the union negotiates for its union members and the one the rest of the workforce negotiates for themselves.  They should not benefit from being freeloaders.  If an individual can go in and negotiate a comparable wage, have at it.  If you find you don't have the leverage behind you to negotiate a similar wage and benefits package, too bad for you.  You (should) get what you pay for.

I swear the right will not be happy until there is no middle class left.