Asbjørn UlsbergFrom line 782 to 788 in the file lib/W3/Plugin/TotalCache.php, the errors are output to the user regardless of the user's role or level. This means that ordinary subscribers gets the "One or more plugins have been activated or deactivated ..." notice, among other things.
While the administrator ideally should hide these messages instantly, it's hard to avoid users seeing this on a heavily used site. As they can't click on any of the buttons in these notices and shouldn't see them at all, I suggest doing a little if (current_user_can('manage_options')) before outputting the notices and error messages.
I hope this can be implemented quickly, as it's a one-line fix that doesn't break anything.
