You cans at least just click modify and just delete everything in the post, but then everyone will be wondering what you said that you wanted no one else to see.
I say the new policy should be: when you make a dumb post, remove everything and replace it with a haiku or a neat story. That way although you have removed your idiocy at least it is replaced with something fun to read for others.**
**coming from someone who constantly wants to delete his posts
Though, I didn't say anything stupid (at least in my opinion), I just said the same thing twice. I think you're idea is a good one though. Replacing with something worthwhile even if it's not relevant...something to think about.
I'd like to think it's impossible that it won't happen, given that John C Reilly's set ends one hour before Tenacious D's. Although there have been some other seemingly inevitable collaborations over the years that never happened.