Just had the second experience of this in the last couple of months: Was composing a post in Gear Discussion on roof boxes, and accidentally hit "clear" instead of "submit." Redid the message, submitted it, only to find that first message had in fact posted although I never hit submit. So I had two basically identical posts. OK, you don't allow deletes, so I hit edit for one, and tried to clear message. No go. System said I needed to have some number of characters after the clear. So I typed in one sentence and hit "submit." Now that should have changed the original message, because I was in "edit" mode. But instead it produced a new, third post with the one sentence. Now there are four posts in a row from me, two nearly the same, a third single sentence that refers to a nonexistent "below," and a fourth that asks someone to just delete the whole mess.
This happened to me a while ago in the boot forum. It's really annoying. I think it's a software bug, because the software does not direct the edit back to the original message that's being edited, but makes it a new post.
More to the point, but this is more a policy issue, members should be able to delete messages they've just posted. Both because of mistakes they've made like my hitting the wrong button that produces software idiocy, but also because they may realize the message is misdirected (wrong forum), based on incorrect reading of another post (say five years old), etc. Easy to do, just put a timer on it, so after a minute or two, moderator has to do it for you, so godlike powers preserved.