Oh, I understand that you create a thread if you don't know who locked it.
When you know who locks a thread(usually they give a reason before locking) PM'ing is a good alternative to flooding the boards.
Whenever a thread is locked, there have been inappropriate behaviour to cause this. Often, its self-explanatory why it happens.
However, there are confusing moderators on every forum and I agree that giving a reason or at least, a warning before locking a thread is a good idea.