If as you state just Googling the search term Tails can get you on the NSA watch list, I wonder how anonymous you truly are.What are the possibilities that tracking scripts aren’t already part of the operating system. Wouldn’t it be the same for TOR and other open source programs.
As far as I know, searching for TOR and downloading TOR as of now gets you put on a watch list and you’re marked as a suspicious criminal in the eyes of the NSA and the FBI and since they both have international reach and a major influence over numerous other countries, I would not be surprised if governments of other countries are keeping a watchful eye on who downloads it as well. I’ve heard that the FBI are now controlling a certain amount of TOR exit nodes but I have no evidence to back this up, so take that with a grain of salt, it’s only what I have heard but it could possibly be true and with that in mind I wouldn’t be surprised if a similar approach is being taken towards tails.
Tracking scripts seems a bit far fetched though, I know the NSA and FBI are extremely well resourced but it’s a known fact that they can’t just de-anonymize any specific exact individual that they would like to, I don’t believe that tails has a backdoor on it and I do not believe that TOR has either, it’s a possibility but I don’t think they have been compromised, if they have, you’d be hearing a lot more on the news about the capture of more and more cyber criminals.
Obviously if you want to download tails without being placed on a watch list, you could use techniques that Nathan has gone over in the lectures, like using SSH, VPN, JonDoNym and TOR etc. You could use for example Debian Linux as your main OS and then have Whonix as a virtual machine and then nest a few anonymizing services on that virtual machine and download tails, obviously don’t leave a money trail if anonymity is extremely important. If you haven’t seen those lectures yet then I suggest that you get around to it and after watching them, you’ll know what to do that will meet your requirements.
I would add that we have a lecture on trust and backdoors in volume 1 which addresses this.