Do Led Throwies really last up to 1-2 weeks?

I've been reading a post in Evil Mad Scientists about the scientifics and workings of Led Throwies and it got me thinking: If a CR2032 has a value of 250mAh (tops), and an LED consumes about 20mA, then doing the calculations (250/20) we have that the battery would run out of juice at about 12hours, then how are led throwies lasting weeks?!! Maybe I'm an idiot and this isn't the right calculation for this kind of thing. Can someone show me the light?

Re-design7 years ago
The lm3909 flashes and also restricts the current going to the led so the battery lasts quiet a bit longer.  If you light the led without  the 3909 it uses full current and the battery doesn't last as long.
Skyriam (author)  Re-design7 years ago
I know, but the "official" statement is that throwies can last up to 1-2 weeks without resistors or something of the sort, just directly connected to the battery.