Snowden had proof and plenty of it. A random border agent that finds some documents on his desk in the morning, to be used that day, does not have much proof.

Snowden had proof and plenty of it. A random border agent that finds some documents on his desk in the morning, to be used that day, does not have much proof. Secondly, a lot of people knew, but kept quiet. I see no reason to expect a random border agent from talking, given it took years and someone like Snowden to finally talk.