I'm an accidental DBA, but also spend quite a bit of time with Systems and Exhange issues. We have a group of people who work closely together on all of above. For that reason, when we put in a web request for support on for example, HP, Cisco, NetApp, Quest, Symantec, and so on, we want any Email response to go to a common shared mailbox. In that way, if the person who sent the request is off when the response comes back, someone else can carry on, upload config files, etc.. This makes sense for us, but it's hard to explain to a vendor. We often waste time on explaining why we are responding instead of the person who originated the support ticket.
I work with a different group of people on SAP issues. SAP does a great job with this issue, because with the right permissions, each of uscan log onto the support site and view and respond to each other's tickets, search for old tickets on the same issue, etc.