in hopes of "somewhat" forcing helpful subjects (more of an encouragement), i have made all default reply subjects to be similar to replies in email.
for example, if someone posts a topic with the subject "feline behaviour changes when confined indoors", a reply will simply include that subject with a "re: " in front.
you can of course edit it out and put in what you want, like "topic is being locked"....but in most cases it's really not needed. keeping it "re: orig subject" also keeps the search engine clean.
hopfully this will promote more helpful subjects as opposed to starting the message body in the subject field.
if you dont get what i am saying, reply and i will clarify with examples.