I can't speak to what system they'll put in for the tolls. You're quite right that the government hasn't indicated they expect this to be a toll bridge. I will say that from an internal control perspective, cash is the easiest thing to steal. With the advent of things like smart passes and credit card payments, the capability for fraud falls greatly. It's too early for me to say what the toll system will be.
On May 27th, 2014. See this statement in context.