Even if I dismiss a badge notification ("You have earned the ... badge for question ...") using the close button at the right of the message it gets redisplayed again and again when I refresh the page until I open a new session.
Working with Safari 5.0.3 (6533.19.4) on Mac OS X 10.6.5.
I just created a new account at writers.se, and all three messages (Welcome, associated with, earned rights) kept appearing even after having gone to meta and back. Only jumping into a question and coming back to the main page made them go away. (Click them away using the close button for each, go into a question, and come back to the main page.)