Time-Turners are not normally locked like Harry's is (which also has the restriction on the time of day when it can be used). For instance, in Prisoner of Azkaban, Hermione uses her Time-Turner to transport her, Harry, and Ron back in time simultaneously.
Then how did Quirrell figure out the restrictions on Harry's Time Turner without so much as laying eyes on it? All he should have known from Harry's temporal discrepancies was that the thing existed. That implies to me that the set of locks Quirrell mentioned are a standard operating procedure, and the only extras that Harry's turner has is the protective shell / locked before 9 PM combo.
See also posts 1816 through 1822 in the TVTropes Methods of Rationality thread.
So the quote is
The snake twitched its head, a snakish nod. "Many resstrictionss. Locked to your usse only, cannot be sstolen. Cannot transsport other humanss. But ssnake carried in pouch, I ssuspect will go with. Think posssible to hold hourglasss motionlesss within sshell, without dissturbing wardss, while you turn sshell around it. We will tesst in sseven dayss. Will not sspeak of planss beyond thiss. You ssay nothing, to no one. Give no ssign of expectancy, none. Undersstand?"
Nevertheless, it seems possible that if Mr. Hat-and-Cloak has a ...
Update: Discussion has moved on to a new thread.
The hiatus is over with today's publication of chapter 73, and the previous thread is approaching the 500-comment threshold, so let's start a new Harry Potter and the Methods of Rationality discussion thread. This is the place to discuss Eliezer Yudkowsky's Harry Potter fanfic and anything related to it.
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven. The fanfiction.net author page is the central location for information about updates and links to HPMOR-related goodies, and AdeleneDawner has kept an archive of Author's Notes.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: