I was running 100CM last night with a group of first timers. We got up to the final boss. Then, due to RL, people had to leave. So I LFGed for more, clearly marking the group as for first time 100CM players. 4 People joined me, then after one run (failed at 16%) demanded to see my title (all of them changed to theirs) and kicked me out when I reminded them the group was for first run people. Essentially, they just wanted to get the completion and stole my last boss instance.
This is why I keep saying we need to remove these kinds of titles. Give a group a method to say "you aren't leet enough for us" and they will use it to discriminate.