Until one of them comes along and tells us "you can't use our textures" who cares no ones told us to stop so why should we?
If one of them comes it's OH that shuts down the next day. It's called a cease and desist letter.
And I work with Google imagery and products every day... so while I'm not one of them you can consider yourself warned

Just kiding OK? But I do work in 3d modeling and heritage promotion using Google Earth (
http://sketchup.google.com/3dwarehouse/search?uq=1166243199703387444023400&scoring=m).
Simply put, to protect the forum and Hangar site (because these posts and addon descriptions are indexed by Google itself...), specially the role of the site owners, we should not discuss any usage of the images other than what's indicated on the TOS.
That covers a print screen in a word document and of course your own personal use to place objects on a surface base. Also, no problem if you paint over the said images, therefore creating your own work.
But an addon that clearly indicates a TOS violation should not be avaliable. The administrators aren't forced to know were the images came from, BUT if it is on the description they should take it down.
I do believe that we have a forum rule preventing any discussion about pirate software, including indications about how to get it. Perhaps something similar might be needed in this case.
Imagine that instead of satellite imagery we were discussing a spacecraft mesh used in any addon.
Would YOU like to see YOUR mesh used in some render that ends up in someone elses portfolio, game, site, etc? It's not about the law, it's about respect for one's work.