I had a non-linguist friend try it today. He got just under 50%, but that was probably skewed by the fact that he's studied Japanese, and 3 of the scripts in the first quiz are used in Japan. Being able to read Japanese kanji gave him recognition of Chinese as a bonus (though he can't really read Chinese). Plus anyone who spends much time in Asian markets gets to recognize Korean pretty quickly.

(That's how I recognize Thai as well-- I was surprised he missed that one.)
Part of the reason I posted this is that I'm wondering how easily our members recognize different scripts, as we now have the ability to create usernames using unicode. If you see a username like 猫神 or नालो, how hard would it be for you to recognize that name again? How about Игор or Αθενε?