Thanks for those references, Blondie. Interesting that the comments seem to err more against women wearing trousers, the later the comments are made! However, I can't see an explicit statement that it is inappropriate for women to wear trousers on JW business. A JW apologist could claim that the WT has never imposed such a silly, arbitrary and old-fashioned requirement. Much as, apparently, it has always been OK to associate with non-witnesses.
Nonetheless, we all knew what was "allowed" and what wasn't!
It boils down to control. People who are capable of deciding what constitutes smart dress might find they are capable of deciding all sorts of things for themselves. And that would never do.