Nothing is safe from civil law suits in the USA. Anyone with deep pockets who is willing to pay an attorney can sue anyone for any reason.
At one time Sony's attorneys threatened me with legal action over the use of their images and trademarked names. They even demanded that my hosting company close my account. The site that they were complaining about happens to be an Amazon affiliate site, so I pointed out that Amazon's TOS allows me to use their images and content. I think they were a little embarrassed due to their stupidity and they withdrew their complaint. However, if I was using the Sony name in a domain name, they would have had a legitimate complaint and I would have lost. You cannot defend the use of a trademarked name in a domain name, especially if it can confuse a user in any way.

