What? The decline button adds a cookie that tells a given website that you've declined any given popup, so that the website knows not go give you this popup again. This means that if you are using a standard web browser (defined as generic firefox/chromium without adblock) said cookie remains for some time until it expires; because yes, keeping any cookie for undetermined amount of time is bad. So if anything your tails gets more popups if they dont store said cookies and use no external tools to block those popups like adblockers. Also yes I know tails is an OS, but I dont get why using it matters in the discussion about cookie popups not storing their declination state for rolls dice 4 years.