We are working with a site that has a number of index pages, by category. It uses URLS of the form /content//, and uses the trailing slash to differentiate between other filters and a category filter. As such, removing the trailing slash results in a URL that is not on the site.
This is done in uriwrapper.rb:194
I understand the desire to canonicalise the URLs, however it might be useful if it were optional for some sites.