London Gatwick airport's page says a simple "your request has been processed", what does this mean? how are my expectations being managed? (they aren't). Which newsletter was this again? Oops, how do I sign back up I didn't mean to click on that! This page looks particularly lazy, possibly not even a web page with any formatting. What makes this worse is that it is from a third party mail list management service ... it doesn't look like the whole user journey is considered equally.
The Brighton Fringe festival and Proud Ballrooms both use the same system, with the same formatting. Plus points for the optional setting of how many more emails to get before the stop emailing you. I'd say a big negative is the white label feel, coming from a branded email the experience is hardly seamless.
The poor sites give vague messages on sites that are little better than placeholders. And you still get emails. And then another one.