OOtP: <Spoiler> Why Weren't the Weasleys in the Order?

[snufflesnbeakie]

No: HPFGUIDX 66052

I might have missed this topic of conversation, if it had been 
brought up previously, but I was just re-listening to my audio tape 
version of OOtP and came across something that made me wonder. . .

When Lupin was reassuring Mrs. Weasley after her terrible ordeal 
with the boggart - he said that she hadn't been in the order last 
time, so she wouldn't have known that it was different: i.e., that 
order members where outnumbered 20 to 1 by death eaters.  This time 
it was different. . .  And they were not in the photo that Moody 
showed Harry.

But why would the Weasleys not have been in the Order the last 
time?  They would have been old enough, they are obviously staunch 
supporters of Dumbledore, they are disliked by death eaters - surely 
they would have been members.  This seems like a huge contradiction 
to me.

Any theories?  If it's been previously discussed, I'd really like a 
reminder of what was thrown out!

Thanks :-)

Beth