Is there a Major Flaw in OOP?

[flussbiber]

No: HPFGUIDX 70472

Well, let me try this again since nobody
responded to my last post. Maybe it has 
been discussed and dismissed, but I 
would still very much like to know, at 
least what other people think about it, 
please?
Is it really only me who thinks it is 
very odd and doesn't make sense that 
the ministry is completely deserted when 
Harry and his friends get there? If 
the Death Eaters can clear the ministry 
so easily, never mind whether it's in 
the dead of the night or not, there is 
absolutely no reason why Voldemort 
shouldn't walk in there and just pick up 
the prophecy, no? Was that what the 
Order was trying to lure him into? They, 
or at least Dumbledore, know that the 
prophecy is rather useless to Voldemort 
now, except that it tells him clearly 
that he has to kill Harry if he wants 
to live (ah, doesn't he now?). No big 
news. Also, as somebody on this list 
pointed out, they could have easily 
destroyed the prophecy if they really 
didn't want Voldemort to get it.

So ...
Question number 1:
Why is there no security in the ministry - either from officials or 
from the Order?

which leads to question number 2:
Why did Voldemort not just go there, unseen and pick up the prophecy?

Question number 3:
Why did Snape need several hours to get worried enough to alarm the 
other members of the Order? Also, didn't Sirius get suspicious when 
Snape checked on him?

I'm not criticising Rowling, at least not yet, I just cannot 
understand this and had hoped that someone in this huge group might 
have been able to help me. Thanks.

Flussbiber