If you select hide poster ID in the thread when you create it only IDs are hidden by default. The poster have to select to hide his/her flag when posting if he/she wishes.
Ah, too bad. I guess I'll just work with what I have then.
Anyone think it would be better if there were a hide all flags option as well?
/mlpol/ is such a tiny community that some posters are easily distinguishable by their flags, and those posters having to single themselves out by hiding their flags isn't really that helpful if the OP wanted a truly anonymous thread.