I have no problem whatsoever with people pasting 100s of smilies in a thread as I can easily avoid that. What can't be avoided is seeing that stupid thread title in the list of active conversations. I don't want to miss all the chat threads just because of it.
People can be as childish as they like in a thread but mucking about with stupid thread titles when it's clearly annoying a lot of people is just plain selfish.
I think thread titles are where you need to show the most consideration for others. It doesn't matter what's in the thread be it swearing, explicit stuff or just downright silly. A thread title should make it apparent what is in the thread so people don't have to see it if they don't want to.
A thread title that is so irritating just doesn't give you that option.