Egypt was renowned for its fabulous wealth. Luxuries and jewelry would've been known throughout the world. Egypt was power and affluence, and the thought of the Jewish people stripping away some of that on their way out would have delighted the listeners of this story. Much of that wealth, the story tells us, is built on the backs of Hebrew slaves, who moved to Egypt and helped bring the people through famine, only to be enslaved later on.
God tells Moses here that the king will not let them go unless compelled. So perhaps they see opportunity, but there is real fear as well. Will this work as God says? How will they know? What might happen if they are wrong?
There always seem to be more questions than answers. God is in the midst of the uncertainty, in the midst of the fear, and God will do wonders in the midst of it all.