Suppose you were a believer in the benefits of canoes. You want as many Canadians as possible to own a canoe. You would presumably want to encourage competition between different canoe manufacturers, so they would compete on price and quality, so that price would be lower and/or quality would be higher, so that more Canadians would want to own a canoe.
Suppose you were a believer in the benefits of unions. You want as many Canadians as possible to belong to a union. You would presumably want to encourage competition between different unions, so they would compete on price and quality [update, to make the analogy clear: of the services unions provide to their members], so that price would be lower and/or quality would be higher, so that more Canadians would want to belong to a union.
Labour economics is not my area. I do not know the laws on competition between unions. I do not know the rationale for those laws.
A close friend of mine works for a federal government department. A few years ago she and her colleagues were dissatisfied with their union. They believed that some other unions would offer a better quality service at a lower price. They wanted to switch to a different union. She said this was impossible to do directly. Instead they would have to decertify their current union, be without a union temporarily, and then invite a new union to represent them. They did eventually decertify their union, but it was a long and difficult process. They are currently without a union. They voted to postpone the decision to join a new union.
Two (sets of) questions:
1. Is it always hard to switch unions? Is this only true in the public sector? Do workers switch unions often? What are the laws that discourage unions competing with each other to represent a group of workers?
2. Why are there those laws that make it harder for workers to switch from one union to another, and discourage competion between unions?
Canoe manufacturers might want to restrict competition between themselves to increase their own profits. But those who want as many Canadians as possible to own a canoe would want to promote competition between canoe manufacturers.
This post has been brought to you by the Canadian content provision of WCI, in a hopeless attempt to offset all the news about public sector unions coming out of the US.
Worthwhile Canadian Initiative 
So Jim, to re-ask my question, based on your post. Why do distinguish between cooperative exercises in the form of partnerships and corporations, on the one hand, and unions on the other. Why is one form something to be skeptical of (at least for some people) while the other is something to be praised (for others)?
unions – most of them, most of the time – are and feel themselves to be part of a labour movement with wider purposes than bargaining with a specific employer. Fighting each other to gain members undermines the goal of solidarity and reorganizing the unorganized detracts from expanding the movement. The CLC does have protocols which discourage raiding while providing a means for members to switch unions based on clear justification.
I meant reorganizing the organized …
On the concept of a union as a business organization, I thought this piece in Today’s star was interest (http://www.thestar.com/news/article/1214758–toronto-schools-pay-high-prices-for-small-jobs?bn=1)
The headline story is about public sector workers behaving badly (or, at least, about suspect internal billing practices and the suggestion that it might have been used to cover for having surplus workers), but the pertinent part of the story for this discussion, is that the arrangement that the Toronto District School Board has with this particular union looks very much like the arrangement it might enter into with a typical contractor, except remuneration is paid by way of wages, rather than fees.
Also, as an aside to other union presidents, when newspapers come calling , cursing them out is likely not the best way to manage the issue.