Well, in theory, in the past anyway. Certainly not the modern American experience with unions - look at our auto makers, forced to pay high-school drop outs 6 figures for jobs that don't warrant more than 10 bucks an hour and abuses like that there. Public unions are no different, except that they basically get to extort even better deals for themselves by virtue of electing their bosses.
Well, you'll have to forgive me, I don't know much beyond US unions besides them being a bit sucky, over here they are generally reasonable.