The notice supposedly should only be shown once, but some people report to have already seen it 20 times. That means that there might be something wrong with the setting/reading of the cookie value.
Lack of attention for issues as these, causes people to add CSS to ignore ALL sitenotices ALWAYS. As such I think that any sitenotice has great responsibility to not muck it up for the rest.
Version: unspecified
Severity: normal