What was DU hiding?

[meriaugust]

No: HPFGUIDX 116012


Since several people picked up on my Fred and George question at the 
end of the last chapter discussion, thought I'd throw my other one 
out there for seperate discussion, just cause I want to know what 
y'all think. 
Anyway, DU states in OP that her fire is the only fire in Hogwarts 
that isn't being monitered by the MoM. Why is that? As loyal to the 
Ministry as she is, what could she be saying that she doesn't want 
anyone, even the people on her own side, to hear? Or are there other 
ways to monitor the floo network other than the specified panel? And 
why would she take the risk (she of the Quibbler banning and 
Educational Decrees and Dementor siccing) that someone would break 
into the office to use her fire for private conversations? Is she 
hiding something? Or has the "DU is a DE" speculation (and all these 
marathon Red Sox-Yankees games) finally gotten to my head? 
Meri