Yup. There is always the possibility that someone will comment on something and then you (or whoever) could edit the original post. That's happened, but it is rare. If I'm going to edit something, I try and do it quickly. If it's a slow day, it doesn't matter. Either way, you can only edit posts on the day that you post them. When BK creates the next day, he locks out the previous day so that it can't be changed.
Otherwise, when you originally create your post, you have the option to "preview" your post and see what it's going to look like before you're done with it. You can preview as many times as you want...up until BK changes the day. There have been more than a few of us who tried to sneak one in at the last minute (or didn't realize how close it was to the end of the day) and when we clicked on the "Post" button, we got the message saying that we can't post...and we've lost our post. I hate it when that happens.