Your 'subject' line becomes part of the index to message text. If you don't intend for your post to be published, simply say so at the beginning in the body of your post and it will be deleted from the SCI mail. If you don't want posts published in SCI Support, just say so at the beginning of posts, so they can be immediately deleted from SCI mail. Weekly, or thereabouts, posts are placed dropped from the primary list of posts and added to a weekly collection. About 2 months later, posts drop from the list of weekly collections and become part of an archive.
Registration is a free, voluntary action, unrelated to posts.
Or, you can ask about something you saw someone do but don't understand. I bet you decide what messages you read based on the subject line. Make the contents of your messsage subject lines useful. But, please try not to quote entire posts, or quote signature blocks. Try to paraphrase related points.