Being mean/sneaky isn't a bannable offense. Neither is lying. And they shouldn't be. Some consequences are deserved in some cases, such as the OP's. However, I think banning people is a bit much.
I will say that the system needs changing, not the policy. Meaning, EME needs to find a fix for the people who continuously get kicked and suffer a harsh CD without really having done the instance. Not a change in harassment policy or a "tightening of the reigns," so-to-speak.
As for what that change might be? I really couldn't say. Maybe the CD fo such dungeons should be lessened depending on how many boss fight you participated in. For example, and these are just random numbers for the sake of an example, but maybe a 5-10 min CD if you fought no bosses, 15-20 if you fought against 1 boss, 30 min for 2 bosses and so on. The only problem I see with this is it could be abusable if the first boss of a major dungeon drops something particularly juicy. I could see people fighting simply the bosses they need to avoid long dungeon CDs. I guess that's why I'm not a dev, eh?
Best thing you can do is look for a few people on your server who wants to run said instance and join LFD as a group until they add a feature to combat this (something similar to WoW's I assume).
I'm sick of people in 138 gear queueing BT :(
What I would really like to see is T12 gear either being BoP OR only being able to use the LFD tool for end-game dungeons if you have previously cleared the instance / achievement using the regular server LFG tool.