I agree. A penalty would open up venues of abuse. However, limiting the person who is kicked not to join the same instance/group is reasonable and probably under the scope of good practice. We recently experienced something similar in a duty finder turn 7 where the tank just had a really bad attitude. After various attempts to get the person to just calm down and stop with the harrasment of particular party members the group decided to kick him/her. The person requeued and joined the same party and then AFk'd.

So we did what anyone in our position would do. We 7 man'd it.

Classy stuff.