Spamming /tell to people does disconnect people if it over-floods them and you can do it on your own with a simple macro like
/tell <name> SPAM SPAM SPAM SPAM SPAM SPAM SPAM SPAM SPAM
/pause 0.1
/m <title>
You'd need to spam the macro about 10 times, and it would disconnect yourself and the person you're sending /tells to.
I do it across servers to people i don't like

and watch them log off (well disconnect actually)
