The problem of spam is that you do not want many false rejections (much better getting some spam through than losing some valid emails). In your example, you s

The problem of spam is that you do not want many false rejections (much better getting some spam through than losing some valid emails). In your example, you say it is easy to see from sender/subject/first line it is a spam, but only because you "know" it is a spam. Could you guarantee the email cannot be spam with 100 % confidence ?