Nope. I've never seen it before and I don't use Adsense or have any Adsense sites. There are tons of 5 Star sites that aren't mine. 5 Star software, 5 Star hotels, 5 star,,, you name it. I wish I owned them all but I don't.
The only other 5 Star you may run into that I own is my blog directory.
5 Star Blogs