Zenmervolt,
It is a dumb idea because who knows what will get discussed in the thread. I know the Big 4 well. They don't want dumbness associated with their name. What if someone with a bad experience with them started ragging on them or other bad publicity gets posted? Plus, he's brand new their and just an intern. Impress them with your work and don't stand out for stupid things.
I look at it this way - what does he have to gain by putting the name in the title and all over the thread? He could have said Big 4 and been as descriptive as he had to.
Mentioning client names would have been the height of stupidity, but it would have started with the firm name.
I've risen very far in Finance and I have a decent idea of what is smart. He probably would have been OK to mention the name, but why take the risk?
Michael