I can
I worked as a prof in a local college that had a "Professional Association" (read expensive union)
When I stated that I would prefer not to join, I was told it was a requirement. But they asked why. I told them, I would rather negotiate my employment conditions as I could do a more effective job representing my skills and their value than a simple grid that listed years of experience and years of education. As an example. I earned the same salary teaching Advanced C Programming (yes this was a while ago) and earned the same salary as the prof teaching a high school math upgrader. My marking alone took many more hours than the multiple choice exams my office mate had.
In 1996 the college went through a downsizing. Since I was the last man hired, I was the first man to be released. The students actually demonstrated to keep me. ( I was the only prof who had actually done real development work in C, the others that they kept actually sat in my lecture in the morning and attempted to reteach in their afternoon block )
At one point, I thought I would try and work with the system. I booked a meeting with my union rep and made a proposal for a 3rd dimension on the salary grid. Course difficulty. I actually had it mapped out quite well with research from the colleges own industry reports where salary would now be based on length of employment, education, and teaching load. Where the classes were ranked on load. This would then become the 3rd dimension to the grid. I even volunteered to present it at the next meeting.
The answer I got was, "This looks nice, but you elected me as a representative, it is my job to decide what should be put in collective agreements. You then vote on what your union officials decree". My proposal never got a second meeting, nor acknowledgment anywhere.
When the downsizing happened, students complained (in numbers) to the dean, I even suggested to some that they try the union. The information I got back from the union was that they agreed with the college about downsizing so that they could maintain the current salary grid for those remaining. Now if you look at this politically. If you want to maintain your rep seat, keep the people that are staying happy. To bad for those released, but they wont be paying dues next year.
Another example of a real union was the Transit Union. When I was going through school, I drove a bus at night to pay for my college. If a driver called in sick, dispatch could force you to drive a double shift, and once I drove a triple shift. However, because money was important, you were allowed to drive a shift for another driver and he would pay you. The only difference was, if you drove more than 48 hrs that week you were not allowed to pick up another shift. Here is the catch, Say you traded your Tuesday night shift to study and picked up someones shift on the weekend, and then on Wed, dispatch forced to drive an extra shift, you would not be allowed to drive the shift you traded for on the weekend because the time system said you had too many hours.
Off I went to the union meeting, asking that this be looked into. The membership in attendance voted almost unanimously, a couple of abstainers, in favor of discussing this with management and looking at it during the contract negotiations. This was the last I heard of the proposal. When I asked about it, I was told more important issues came up. Some of the items that did get negotiated were absurd at best. "Seat covers for the drivers seat" for example.
In the end any union or prof association I have ever belonged to has only managed to lower my salary to what I have been able to negotiate myself, collect fees from me, and not carry forward any of my concerns. Most were more interested in keeping their own rep posting.
Last example. My father owned a tin smith shop. He employed approximately 30ish tradesmen. One day a few of them got together and decided that it was time that the shop become a union shop. Sometimes you have to wonder about the intelligence of some people. The end result was, Dad lowered their wages to the union rates. took away the perks like taking the company trucks home. A couple of them lost vacation time. The guys then started to grumble, and this was then the final excuse dad needed to retire. He sold the shop to a new owner that new nothing about the business. In two years, he ran it to the ground. The shop closed, and everyone became unemployed. The union really helped out here :)
Any organization should always ask "Are we still required", There was a time unions had a place, but all I have seen most do is protect the lazy worker, collect dues (take away from my salary), ensure I can only obtain an "average" (at best) salary, and occasionally give up all of my income for a few months when people want to strike for issues that I could care less about.