Interesting view that the unions ensure pay rises that wouldnt have happened. Its not been my experience, through a few different industries I haven't seen the unions able to get significantly more pay at any of them. I have seen them secure pay rises when they wouldn't have been given, I have seen them manage to negotiate a lower rise than the company would have given if they had pushed hard enough though

Ie company budgetted 4%, initially offered 2% knowing that no matter what they offered unions would reject, or ballot to reject to be 100% correct. Final agreed rate was 3.5%, without the unions the company would have given 4%.
So the management offered 2% although they could have afforded 4% and it was only due to collective bargaining that they received 3.5%.
Seems like an improvement that the collective bargaining right s of the workforce gained over what the original offer was.
What industries and a what levels have you been employed. It must be at least at board level to have intimate knowledge of the original intention to offer 4%.
(not that I believe you example to be anything other than illustrative, as any shareholder would be horrified to think that their board was willing to offer over the odds in pay increases without negotiation, either through Unions or direct employee consultation.)
Re managers and supervisory level staff not following legislation etc, surely the senior managers should be the ones ensuring this is applied not the unions. Thats how it works in non unionised places of work, having to have legislation advised by the unions means either the lower managers are failing or the senior ones are failing. The fact the unions are advising is a failure of one of those levels not a benefit of having unionised working.
In small compact business models you would be correct, however in my industry it is impractical to supervise the day to day compliance personally and we rely upon both management and the workforce to make sure all legislation is met and adhered to, this is a legal requirement for ALL employees and it is is practical to have union representatives who report upon such adherence at all levels. Legislation plays an important part in our overall ability to function effectively. What you find in non unionised companies within the transport industry is an increased incidence of non compliance and the respective problems that brings, such as the loss of operators licences and answering directly to the Commissioner.
Invoving the Unions and therefore the workforce in operational compliance is a cost effective and inclusive way to foster cooperation and increased vigilance within our compliance structures.
Like I said, it is not as black and white as you make out and unions do have a place in the industry, it is militancy that does not. Their is a significant difference between the two, one which I do not think you are aware of.
Personally I dont think unions should be involved in pay in modern society, ensuring that union members are treated fairly and ok if they have weak management ensuring that rules are followed is great, but making out that people would still be paid 5p an hour to do jobs just because the union aren't there to negotiate wages isn't correct, over time assuming basic protection (which comes from elsewhere not unions) all jobs will seek out a market rate balancing supply and demand. All unions seek to do is these circumstances is to beat the system and get paid more than the companies believe they would pay.
In the real world however not all management or indeed companies are fair and even handed in their approach to their workforce. If they were then there would be no need for unions, however the real world is not like that and for many industries the need for unions and the protections they offer to their members is still a necessary and useful part of employment.
Better working relations between management and the workforce, either through unions or employee forums is a good way to do business. Germany is a prime example of good Employer-Union cooperation for the benefit of all and if we can remove poor management practice and remove the needs and causes for union militancy there is no reason why this country cannot benefit as well.