One thing I meant to mention as well is the following ‘asymmetrical’ behavior:
Once the Watcher list is set up via RT Web interface, then it is ok to conduct collaborative communication via email – with the caveat that only the RT-queue email address is the email recipient and the Subject line contains the ‘[rt-queue #123]’ (or something like that) tag.
Again, as far as people who are collaborating on a particular RT request are concerned, email replies should be sent to RT queue email address only. RT server is the one that will forward the email mesg to the people on the Watcher list for that ticket.
It’s kinda weird that you have to manage Watcher list via RT Web interface, the but actual communication amongst the people can be done either via the web interface or email. It would be nice if I can do all that via email, but I don’t think it’s possible (without some heavy hacking made to RT).