Sneaky...

Go here... Copy-Paste from Website to Terminal
DO NOT paste into Terminal, paste into Textedit or something.
Freak out.
Now look at the page source for the site. Something to think about.

Sneaky indeed. I'd like to think that common sense would alert people to this when they pasted it but, well, who knows.

I wonder if the "display: none" CSS property would achieve something similar.

I tried it (because I knew what it did). It barely registers in Terminal it runs so fast because there's a linefeed at the end. You cant just paste and look at it before it runs.
Don't know enough about CSS to comment.

Just tried it, "display: none" doesn't work. It looks like it works by hiding itself with that code block (the one with the git command). This would explain why "display: none" didn't work.