I am a manager in the Operations Department of the regional 9-1-1 centre in Vancouver BC Canada... and I know this happens ALL OVER THE WORLD!
In our centre, we deal with about 1.25 Million 9-1-1 calls a year.. that works out to a little over 2400 a day! Of those, we *average* about 300 misdials/accidental 9-1-1 calls per day.. each one either a cell phone in someone's pocket, backpack, or purse.
In my humble opinion phone designers and engineers have a tough task: Try to design a device that allows access to the 9-1-1 call when there is a true emergency (maybe what? a one in ten thousand chance that call will need to be made?) ... while balancing the form and function of the device for its everyday use! Its not an easy task.. and I think RIM and all the others are doing their best.
The approach we took where I work is public education. We did a massive public education campaign via radio, and newspaper, with catchy ads about how your "pants" can dial 9-1-1 etc.. we got a lot of press from the local and national news agencies... and wham.. our "accidental cell phone" calls dropped by about 20% ... thats a good start!
This will never go away.. its part of the business.. and I would MUCH rather have my staff deal with all of the accidental ones.. and make sure people are safe.. then have the designers of the phones make it so difficult to make an emergency call that someone doesn't get the help they need... oh lord think of the lawsuits LOL
Like many things in life.. its about balance.. and managing expectations