It's one thing for having software that allows to log in with any name other than the user name the person registered with...it's another that the person comes online as someone else...I certainly wouldn't want to be impersonated by anyone, and their actions happen to change the image in a negative way, which would have an adverse effect of credability that I had already made for myself.
As for the ettiquette of the chat room, it seems that it really hasn't changed much in that sense. Some people will still ignore some others that come online, while others would (or may) take light of someone who's trying to get support for having a bad day. Yet, since this has no interraction with voice and such, it is very hard to catch the tone to whether someone is doing/saying something to help lift the other person's spirit, or whether they are being insensitive about it.
The issue of being able to log in as anyone should be brought to the attention of Jeanne, or Ennio. I guess as far as how people act, everyone may just have to "police" themselves.