What are you even talking about, how could editing posts be used for the bad? If somebody is going to scam, they're going to scam, not having an edit button isnt going to prevent that. I think you should be able to edit posts, at least FOR SURE in the b/s/t forum.
Why?
For example I posted a sale thread today. And for some reason my photobucket account is fucked and was posting the wrong pictures, pictures that dont even exist in my account anymore, so people saw a bunch of pictures of the wrong skis, and since I can't edit or delete, I had to PM a mod to delete it for me.
Then when I got a new photobucket account and made a new thread, I realized I made a mistake and said one of the skis had a different pair of bindings on it than it did. But of course I can't edit the post so I cant change it. So I mentioned it a few responses down which nobody is going to see.
Get over the whole "omg no no no we can't have a edit/delete button because then we can't make fun of nooooobssss as well because they can edit the embarrassing shit they said omgggzzz!!!!1111" bulllllshit.
Its fuckin 2009, get a fucking edit/delete function.