Have they ever contradicted the pledged delegate total?

No. Since they were established beginning in the 1984 presidential cycle as a way to give party leaders more say in the process, superdelegates have never changed the outcome of the primary season. "The superdelgates are politicians, and politicians generally try to agree with voters and follow the will of the voters," said Elaine Kamarck of the Brookings Institution, who was on the 1980s commission creating the superdelegates. But Kamarck - who happens to be a superdelegate supporting Clinton - says they view that voter will with more of a national than state-by-state focus.

http://www.nbcnews.com/politics/first-read/how-do-superdelegates-work-here-s-what-you-need-know-n554136

The DNC has been corrupted by money.


The Reason Why Dozens of Lobbyists Will Be Democratic Presidential Delegates
ABC, Feb 2016

On July 25, these superdelegates will cast votes at the Democratic National Convention for whomever they want, regardless of primary and caucus outcomes. Democrats like to describe superdelegates as mostly elected officials and prominent party members, including President Obama and former Presidents Bill Clinton and Jimmy Carter.

But this group, which consists of 21 governors, 40 senators and 193 representatives, only makes up about a third of the superdelegates.

Many of the remaining 463 convention delegates are establishment insiders who get their status after years of donations and service to the party.

Dozens of the 437 delegates in the DNC member category are registered federal and state lobbyists, according to an ABC News analysis.



http://abcnews.go.com/Politics/reason-dozens-lobbyists-democratic-presidential-delegates/story?id=37289507

If he gets 42%, that's a 16 point blowout that would net Clinton around 40 delegates, and would be a back-breaker for Sanders.

Clinton would be free to turn her attention to the Republicans as the presumptive nominee.

We has it