ALChemy29 Oct 2005

Blatant tends to be intentional. ie. A blatant lie.
Flagrant tends to be obvious and usually a violation of some rule or law. ie. A flagrant foul.
(Notice an intentional foul is something different and could technically be called a blatant foul if the term were to be adopted.)

You won't likely find this distinction in a dictionary but it's about the easiest rule of thumb to go by. Both reflect you in a negative light. Like saying my symbols are obvious and bad and that's the way I intended them.