OOP: Another "ARGH!" moment

[txjen70]

No: HPFGUIDX 67624

When Harry thought Sirius was being held and Hermione insisted he 
try to contacted him first, they concocted this elaborate plan to 
get Umbridge away from her office and to have lookouts.  Wouldn't it 
have made more sense to just take the Maurader's Map and have 
someone keep an eye on it at all times?

To be honest that was just one of many "ARGH" moments in that whole 
equence of events.  Here are a few others...  

Why didn't they remember that Snape was a member of the 
order? "ARGH!"

Why didn't Harry ever open the package Sirius gave him? "ARGH!"

Why didn't they just Floo Powder it to the Order Headquaters and/or 
the Ministry instead of taking the Thestrals?