Decision to Unionize: How does Voting Method Impact the Outcome?

This morning I came across an article discussing Delta Air Line's recent merger with Northwest Airlines and the struggles the airline is facing in getting past the union vote. Historically, Delta's employees have been relatively non-union where as Northwest's employees were mostly unionized.

http://www.ajc.com/business/union-issues-still-vex-199500.html

Recently, a change was announced in the voting method for the union vote. Instead of requiring a majority of 'yes' votes from those eligible to vote, the decision on whether or not to unionize will only be made on those that actually vote. The article states:

"A switch in the election rules to a “yes-no” vote as proposed would mean that instead of needing approval from a majority of those eligible to vote in order to unionize, unions would only need a majority of those who actually vote — which generally is a far smaller number."

This brings up the concept that the voting method selected greatly impacts an individual's or group's strategy for strategic moves. In this example, Delta does not want to have unionized workers. In the past, the company has encouraged it's employees to tear up the union voting forms as a protest against the union. However, with the change in the voting method, Delta now needs all of its eligible employees to vote against the union. As this requires a big change in behavior, it's unclear if the airline will be able to motivate its flight attendants and ground workers to vote.

So the big question is: Will what was supposed to be an 'easy-win' for Delta become a battle between management and employees simply because of a change in the voting method?