Nothing scares web visitors like a security warning message when visiting a web site, particularly if that web site holds your financial records. Imagine my surprise when I went to google.com/adsense and after getting redirected to https://google.com/adsense I get a security warning that the Security Certificate is not valid! Here's what visitors see when using Safari:
and when using Firefox for the Mac:
Google, I suggest you guys fix your redirect to point to https://www.google.com/adsense instead. And it probably wouldn't hurt to spring the few hundred bucks for a security certificate for google.com too! ;-)
This issue probably isn't isolated to just the AdSense site, so it would be worthwhile to check all your sites for this issue.