This is one of those niggling little things that probably have a low priority in the continuing right-now, but sooner or later it will have to be dealt with. Chrome at least is tightening up the rules on the delivery of mixed content to web pages, and eventually non-secure content in a web page delivered over a secure connection is probably going to be blocked. I know there have been several articles on this by Google staffers, I'll try to find one or two of them to check the timescales involved.
SiteAdvisor Red/Yellow warning pages are delivered over a secure HTTPS connection. Those pages are then filled with elements which are delivered over HTTP, which is not secure. The Chrome browser console window shows numerous warnings which will, one day, become errors. The SiteAdvisor blocking pages will then be unintelligible.