To expand on that slightly, what about increasing the edit time before a post becomes uneditable? Though I do agree with editing the subject, but I think as the mods have the ability to edit/change unfit content.
Well, last year I made a post whose subject line should have said 'My First Site Is Up" But I discovered that it said 'My First Stie Is Up'. I had to send a sticky to a mod asking them to correct it. Now, I wish I had left it that way because at least it was funny.