We use a Skype chat for the company, and when people leave the company, it is impossible to kick them out, because the only way to leave a chat is by yourself. Sometimes they have started to use Skype because of our company policy, and they loose or forget their passwords when they leave, or they want to create a new account and they loose the old account info, so they just have hard time to motivate and succeed in clearing themselves from OUR chat...
I wish in 2.6 there could be op or admin status for the first person on a chat, and later for anyone he grants it.