Why didn't Voldy tip off the ministry about break-in at MoM...

[Kashelkar]

No: HPFGUIDX 92912

Kashelkar:
Also, even towards the end when Voldemort lures Harry and the members of DA into the dept of Mysteries, isn't it the simplest just to tip off the Ministry officials (Lucius telling Fudge) of the illegal break-in, and the Ministry officials alongwith aurors would simply arrest the DA members, expel them from hogwarts and punish them severely, (what Fudge, umbridge are dying to do for long...)

Also, the members of the DA (including Sirius) who are rushing to MoM shall fall in the hands of Fudge as an additional bonus.

Pippins writes:

Lucius would have had to explain how he knew Harry was coming. I also think Voldemort expected Harry to show up alone...Voldemort isn't supposed to know about the DA or that Harry has told Snape about his vision...Of course he may know more than he is supposed to, but unless he wants to make it plain that he has a spy in the Order, he has to behave as if he doesn't, always the Catch-22 of espionage. 

Also, your plan doesn't allow Harry to get the prophecy, which was the point of the exercise as far as Voldemort was concerned. 

Kashelkar replies:

I don't really think that Lucius would be required to explain anything, as Fudge and Umbridge (and other people on their side) seem to be so bent on punishing Harry, that he wouldn't demand any explanations at all. Even if he has to, he can always tell that Draco (who is at Hogwarts) informed him. (Also, I've used Lucius's name as an example, it could be anyone.) Also, Harry not being alone is not a problem for Voldy, anyway the MoM people and aurors are going to deal with the gang (ie. Harry and DA members). Also, as I said earlier, the members of the Order(including Sirius), who rush to the MoM on Snape's message, will get caught by Aurors as a bonus, this is a by-product of the plan and Voldy need not be aware of this in advance.

As regards the plan of Voldy, I believe it is 1) to kill Harry, and 2) to rule the world (Conquer the Death). And getting the prophecy is just a step towards it. By tipping off the MoM about the break-in, Voldy shall definitely achieve Harry's expulsion from Hogwarts. And under given situation, I won't be wrong if I expect Fudge to put Harry in Azkaban. If this can be achieved, then the prophecy thing doesn't matter, does it??