I was wondering – say you start a thread on Point A, which gets discussed and covered to your satisfaction. But then the discussion heads off on a tangent about Points B & C, and maybe even turns into a pissing contest between some over-inflated egos.
Should you, as the OP, request that the thread be closed? Or should you just walk away and let the train wreck go on?
I just don’t know what board etiquette is in these situations.
I would say, in my opinion, that you can indeed request that a thread be closed as the OP. Best to email the mods, or report your own post. Whether the mods decide to close it then is up to them.
If you want to distance yourself from people who are “pissing on your behalf” then you should state that on the thread. Something like:
This thread seems to have gotten out of hand, far off the intention of the OP. If someone wants to close it, that might be best.
Then push the Report to Moderator button. That way they have the link to go to, and if they don’t at least your concience is clear.
Thank you for the advice. It’s not so much ‘distancing myself’ from the battle, more like feeling awkward that I set up arena for the fight to occur. Like having a vehement abortion argument break out in the middle of your dinner party, you know? Not your fault, but…
You always have the opportunity to request that a thread be closed, StarvingButStrong, for whatever reason. Whenever you think it’s a “hey, this ain’t right!” situation, call the mods.
It’s better than a dinner party – at least you haven’t wasted money on the catering. 
As the original poster we usually give you the option whether you want your thread closed if it gets hijacked into a pissing contest. And we usually will, if you request it.
For that matter, the mods can (and often do) close a brutal thread even without request from the OP. Which is just as well; sometimes the OP is the reason that the thread got ugly.