Even if there were five cute disclaimers, suggesting that command would still be irresponsible. The problem is that it hurts the people who are the least knowledgeable. Anyone with a modicum of experience downloads the script first, finds out it's 475 lines, and then chooses a different method that is at least tracked by git.
At least get rid of the wholly-unnecessary sudo. At that point, it would at least be comparable to tar xvzf rust.tgz && ./rustc (still less auditable though).
